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		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=317142</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=317142"/>
		<updated>2017-10-26T07:50:41Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brain's weight but contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence key historical discoveries, current research and animal models will be discussed. Towards the end of the page there are future questions listed on future investigations involving the cerebellum and the abnormalities from an affected cerebellum are also highlighted. Terms that may be difficult to understand have also been identified and defined.&lt;br /&gt;
&lt;br /&gt;
The following video provides a brief overview on the cerebellum which will be further discussed on this page:&lt;br /&gt;
&amp;lt;html5media height=&amp;quot;315&amp;quot; width=&amp;quot;560&amp;quot;&amp;gt;https://www.youtube.com/watch?v=Fir-v6EoZNE&amp;lt;/html5media&amp;gt; &amp;lt;ref&amp;gt; 2-Minute Neuroscience on Cerebellum. (2015). Retrieved October 25, 2017, from https://www.youtube.com/watch?v=Fir-v6EoZNE &amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;File:CerebellumDiv.png. (2016). Wikimedia Commons, the free media repository. Retrieved October 24, 2017, from https://commons.wikimedia.org/w/index.php?title=File:CerebellumDiv.png&amp;amp;oldid=226277429.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system: Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;400&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;1100&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
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&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
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There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|'''Figure 14:''' Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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==Neural Development==&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum. There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tube. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tube does not close effectively.&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain.png|500px]]&lt;br /&gt;
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'''Figure 5:''' (Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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'''Figure 6:''' (Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
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*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
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*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
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*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
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==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cerebellum Developmental Weeks==&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
|&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
|  [[File:Stage9 dorsal.jpg|200px|thumb|'''Figure 7:''' Early stage of neurulation&amp;lt;ref&amp;gt;2017. '''Embryology''' ''Stage9 dorsal.jpg''. Retrieved October 15, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Stage9_dorsal.jpg&amp;lt;/ref&amp;gt;]] [[File:Stage10 bf5.jpg|200px|thumb|'''Figure 8: '''Late stages of neurulation&amp;lt;ref&amp;gt;2017. '''Embryology''' ''Stage10 bf5.jpg''. Retrieved October 15, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Stage10_bf5.jpg&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb|'''Figure 9:''' Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|'''Figure 10:''' Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|'''Figure 11:''' Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|'''Figure 12:''' Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
[[File:Second Trimester Cerebellum.jpeg|200px|thumb|'''Figure 13:''' Inferior image of a fetal cerebellum at second trimester&amp;lt;ref&amp;gt;Nuchal Fold Edema. Retrieved October 15, 2017, from http://www.fetalultrasound.com/online/text/2-006.HTM&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 15:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation.&amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 16:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Overview of Development==&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
==Overview of Cerebellar Cell Development==&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers; layers are shown in Figure 15. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
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==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 17:''' Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 18:''' SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===Proliferation in the EGL===&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP). &lt;br /&gt;
===Exit from the EGL===&lt;br /&gt;
BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|300px|thumb|'''Figure 19:''' Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;Zhang, G., Assadi, A. H., McNeil, R. S., Beffert, U., Wynshaw-Boris, A., Herz, J., . . . D'Arcangelo, G. (2007). The Pafah1b Complex Interacts with the Reelin Receptor VLDLR. PLoS ONE, 2(2), 252nd ser. doi:https://doi.org/10.1371/journal.pone.0000252&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===FGF and the Isthmus===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
===Reelin and purkinje cells===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
===Transcription factors===&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Key Historical Discoveries=&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Year'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;500&amp;quot; |&amp;lt;center&amp;gt;'''Discoverer''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;700&amp;quot; |&amp;lt;center&amp;gt;'''Description '''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1500s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Galen, Vesalius and Varolio&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Described the macroscopic anatomy of the cerebellum&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Late 1700s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Luigi Rolando, Pierre Flourens, David Ferrier&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Ferrier's findings of cerebellum.gif|220px|thumb|right| '''Figure 20:'''Ferrier's findings on a monkey's cerebellum with stimulation points discovered&amp;lt;ref&amp;gt;Sabbatini, R. M. (1997, March). Brain Maps The Study of Brain Function in the Nineteenth Century. Retrieved October 26, 2017, from http://www.cerebromente.org.br/n01/frenolog/frenloc.htm&amp;lt;/ref&amp;gt;]] &lt;br /&gt;
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Provided experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens, Luigi Luciani and David Ferrier were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Ernesto Lugaro&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | First defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Joseph Babinski and Gordon Holmes&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Mid 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt; Ramon y Cajal&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|220px|thumb|right|'''Figure 21:''' Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] &lt;br /&gt;
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Refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed. &lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1880s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Olof Larsell&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1960s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;John Eccles and Janos Szentágothai&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Purkinje Cell Arrangement.png|220px|thumb|right|'''Figure 22:''' Modular organisation of the cerebellum purkinje fibers by Janos Szentágothai&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;23335884 &amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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Pieced together the first complete map of the functional anatomy of the cerebellum and define the excitatory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex.&amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
|}&lt;br /&gt;
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&lt;br /&gt;
=Animal Studies=&lt;br /&gt;
==Animal Models==&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
[[File:Isthmic Organiser.png|310px|thumb|'''Figure 23:''' The Isthmic Organizer (IsO; shown in yellow) forms at the boundary of the posterior midbrain and anterior hindbrain: the IsO secretes Fgf8 and other growth factors, and is essential for defining the regions of the neural plate that will become the posterior midbrain (shown in blue) and the cerebellum (CB; green). &amp;lt;ref name=&amp;quot;PMID3870571&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”/&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
[[File:Zebrafish.jpg|210px|thumb|right|'''Figure 24:''' Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be corresponding to the deep cerebellar neurons in mammals.&amp;lt;ref name=”PMID21309081”/&amp;gt; The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;220&amp;quot;| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|220px|thumb|center|'''Figure 25:''' Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|220px|thumb|center|'''Figure 26:''' Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|220px|thumb|center|'''Figure 27:''' Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|220px|thumb|center|'''Figure 28:''' Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
|&amp;lt;center&amp;gt;'''Medulloblastoma'''&amp;lt;/center&amp;gt;&lt;br /&gt;
|Medulloblastoma is a type of paediatric cancer of the cerebellum that occurs due to an over-proliferation of granule cell precursors in the External Germinal Layer.  These frequently occur from an activation in SHH and Wnt pathways, disrupting the normal transient proliferation in the EGL.  Therapies that promote differentiation of granule cells from the granule cell precursors in the EGL such as BMPs have shown to mitigate the disease &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Symptoms include headaches, nausea, vomit, tiredness, tilting the head to one side, difficulty in walking and balancing and problems with other motor skills. However these symptoms vary from patient to patient &amp;lt;ref&amp;gt;Medulloblastoma. (2017). Retrieved October 26, 2017, from https://www.mdanderson.org/cancer-types/medulloblastoma.html&amp;lt;/ref&amp;gt;. &lt;br /&gt;
|&amp;lt;center&amp;gt;[[File:Medulloblastoma.jpg|220px|thumb|center|'''Figure 29:''' Brain magnetic resonance imaging of pediatric medulloblastomas: ( a) sagittal post-gadolinium WNT tumor; ( b) axial T2 of a SHH tumor. Red arrows delineate the tumor/leptomeningeal disease.&amp;lt;ref name=”PMIDPMC5490254”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5490254&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Current Research= &lt;br /&gt;
==Emotional memory in depression==&lt;br /&gt;
[[File:Screen Shot 2017-10-26 at 10.20.18 am.png|thumb|'''Figure 30:''' In this image you can see differences between the two groups of gray matter density in the cerebellar subregions. Cool color: decreased gray matter density in depression; Warm color: increased gray matter density in depression. &amp;lt;ref name=”PMIDPMC5516611”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5516611&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Past investigations have concluded that damage to the posterior lobule of the cerebellum can cause individuals to show changes in manner or emotional instability, similar to a degree of depression or psychosis, without an outward cerebellar motor syndrome&amp;lt;ref name=&amp;quot;PMID16434422&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16434422&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is highly suggestive of the cerebellum's role in emotional memory despite its involvement with motor control. Patients with Major Depressive Disorder (MDD) display a tendency to only selectively recall aspects of scenarios that match their moods, conforming with the &amp;quot;mood-congruent memory (MCM)&amp;quot; theory &amp;lt;ref&amp;gt;Gilligan S. G., &amp;amp; Bower G. H. (1983). Reminding and mood‐congruent memory. Bulletin of the Psychonomic Society, 21, 431–434)&amp;lt;/ref&amp;gt;. This study was undertaken with that principle in mind, and investigated the depth of cerebellar involvement in emotional memory in depression. A link between the volume and density of cerebellar gray matter with measurements of emotional memory was hypothesised. &lt;br /&gt;
&lt;br /&gt;
The experiment was conducted between patients with Major Depressive Disorder (MDD) and healthy controls (HCs)&amp;lt;ref name=”PMID5516611”&amp;gt;&amp;lt;pubmed&amp;gt;5516611&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Patients with MDD displayed an atrophy in both gray matter and white matter, most severely in the posterior lobule. There was a significant impairment in emotional memory and decreased volume of the cerebellum in both anterior and posterior lobules. There was marked abnormalities in cortical density, but only a reduction in volume was found to be associated with decreased emotional memory. The severity of depressive symptoms correlated with both volume and density reduction in the grey matter. &lt;br /&gt;
The posterior, anterior and flocculonodular lobes of patients with MDD displayed marked structural differences from the healthy controls, and a functional connectivity between lobules VI and VII of the cerebellum and the cerebrum could indicate that the decreased density in the lobules of MDD patients contributes to alterations in this connectivity. The flocculonodular lobe is especially implicated in MDD. The lobe is associated with vestibular regulation;  Soza and Aviles (2007)&amp;lt;ref name=”PMID17074443”&amp;gt;&amp;lt;pubmed&amp;gt;17074443&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; found that patients who experienced vestibular vertigo also experienced depressive symptoms. This study also determined that patients who experienced depression also experienced bouts of dizziness. Thus, an unprecedentedly widespread area of the cerebellum is displayed to be connected with emotional memory, in particular, with positive or negative memory retention and could lead towards a cure for depression. &lt;br /&gt;
&lt;br /&gt;
==Dystonia==&lt;br /&gt;
[[File:Cerebellum Dystonia.png|thumb|'''Figure 31:''' Direct comparison of dystonia scores for animals with torsinA knockdown in the cerebellum alone (TorsinA CB, N = 20) compared with mice with knockdown in the cerebellum and basal ganglia (TorsinA CB+BG, N = 3) at three representative time points; 3 weeks, 11 weeks , and 13 weeks post-injection. There wasn't a significant difference in dystonia score between mice with torsinA knockdown in the cerebellum alone compared to those with knockdown in the cerebellum and basal ganglia &amp;lt;ref name=”PMIDPMC5340526”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5340526&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
This investigation into a potential link between dystonia -a disorder where muscles contract involuntarily- and the cerebellum attempts to delineate its pathophysiological role in the disease &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;5429509&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; . The main concern is that the etiology of dystonia appears to be extremely varied, and as such, unpredictable. There is no significant neural degeneration, but in secondary cases there may be structural lesions present in tissue which could be areas of pathophysiology in dystonia &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;27173653&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Dystonia may manifest itself in almost any body part, indicating that the neural area responsible most likely must not be very specific. This in combination with the involuntary nature of dystonia seems to indicate that the cerebellum is the more than likely involved in the disease. &lt;br /&gt;
&lt;br /&gt;
Basal ganglia abnormalities are hinted to be a causative agent in dystonia.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;9679773&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The gap in the knowledge of the true interactions between basal ganglia and the cerebellum with regards to dystonia have led to a hypothesis; that the difference in basal ganglia malfunctioning versus abnormal interaction between the ganglia and the cerebellum could reflect the heterogenous pathophysiology of dystonia; either primary or secondary. Some experimental evidence currently available implies that cerebellar dysfunction could affect the topographic distribution of the symptoms of dystonia, and therefore further research is warranted to investigate the full depth of basal ganglia involvement in the disease. &lt;br /&gt;
&lt;br /&gt;
==Adaptation to Delayed Action Effects==&lt;br /&gt;
[[File:Adaptation Cerebellum.png|thumb|'''Figure 32:''' In real stimulation, a considerable increase in pre-stimulus low-frequency activity is only found in the right cerebellar hemisphere (near to the stimulation site). But in sham stimulation, pre-stimulus low-frequency activity increases in both the right cerebellar hemisphere and cerebellar vermis.&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.]]&lt;br /&gt;
Sensory attenuation refers to when individuals filters unnecessary information. When there is a perturbation between actions and the following-sound, the sensory attenuation is reduced &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
An example of perturbation is when there is a delay when an individual presses a button with sound immediately expected, but instead the sound is delayed. Sensory attenuation can be further described by the forward model theory. The forward model theory suggests that predictions for sensory consequences (for example, sound that is heard) are made simultaneously with the motor movement&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Predictions and real sensory input (what really happens), after the sound delay is conducted, are compared in the model. If the prediction and real sensory input do not matchup, sensory attenuation is observed. The prediction errors are then relayed to other brain areas for further processing&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
The process of sensory attenuation usually re-emerges after the disruption to the normal mechanism &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The re-emerging of this is a process of either correcting previous predictions or updating initial forward models to minimise prediction errors. The cerebellum is currently being researched on how it plays an important role in updating the forward model within the brain&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. One investigation seeks to find evidence on the involvement of the cerebellum in learning to predict the unexpected delays. This investigation has found that low-frequency activity in the cerebellum, prior to the stimulation, plays a key role in adapting to the delayed stimulus &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
==Addiction==&lt;br /&gt;
[[File:Addiction Cerebellum.png|thumb|'''Figure 33:''' Nissl staining showing the dopamine receptor expression within the cerebellum of a songbird &amp;lt;ref name=”PMIDPMC2904815”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2904815&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
The cerebellum has only recently been suspected to be involved in addictive behaviour, as some arguments provided for the initiation of research into the cerebellar role on addiction&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26602022&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum is shown to be intrinsically linked with dopamine release and reception&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;16451810&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;; with dopamine being the main hormone on which addiction is predicated, it is likely that the cerebellum could influence the response to the addictive stimuli. It has also been established that addictive drugs cause specific molecular mechanisms, changes in synapse plasticity&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;10224304&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, and influence intracellular transduction pathways as well as gene expression in the cerebellum&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25262781&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The specificity of the drugs in targeting the cerebellum could highlight the link between the affected organ and addictive behaviour. Addictive drugs such as cocaine have been demonstrated to produce a behavioral sensitivity in mice, and an associated change in cerebellar plasticity. The change of the morphology of Purkinje cells and synaptic terminals in the mice most likely contributed to the difference in reception of the drug&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25619460&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, this link has not yet been fully investigated. &lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Although there are numerous articles and ongoing research on the cerebellum, there are still investigations yet to be performed. Some questions that could be answered in future research include:&lt;br /&gt;
*Is the cerebellum size related to human intelligence?&lt;br /&gt;
*Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
*What changes in cerebellum development lead to the social impairments seen in those with Autism Spectrum Disorder?&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;28150911&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
*Do we need the cerebellum to actually function and survive?&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
*'''ApoER2''' – Works with VLDLR and is a very important receptor in the brain affecting neuronal function and development. &lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
*'''Dopamine''' – neurotransmitter and a precursor of substances including adrenaline. &lt;br /&gt;
*'''Eurydendoid cells''' – cerebellar efferent neurons.&lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
*'''Hoxa2''' – a gene that encodes for a transcription factor which could be involved in the development of the positioning of the hindbrain. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
*'''Otx2''' – a protein that is involved with defining the layers and regions of the cerebral cortex and cerebellum.&lt;br /&gt;
*'''Perturbation''' –  (In the context of the Current Research) alternation to the normal mechanism that would happen in response to a stimulation &lt;br /&gt;
*'''Plasticity''' – the brains ability to change at any age. &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
*'''Tentorium''' – fold of the dura mater forming division between cerebrum and cerebellum.&lt;br /&gt;
*'''VLDLR''' – Very-low-density-lipoprotein receptor, it’s a transmembrane lipoprotein receptor&lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Cerebellum_Dystonia.png&amp;diff=316238</id>
		<title>File:Cerebellum Dystonia.png</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Cerebellum_Dystonia.png&amp;diff=316238"/>
		<updated>2017-10-25T23:52:15Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;Direct comparison of dystonia scores for animals with torsinA knockdown in the cerebellum alone, compared with mice with knockdown in the cerebellum and basal ganglia, at three representative time points; 3 weeks, 11 weeks , and 13 weeks post-injection. There wasn't a significant difference in dystonia score between mice with torsinA knockdown in the cerebellum alone compared to those with knockdown in the cerebellum and basal ganglia &amp;lt;ref name=”PMIDPMC5340526”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5340526&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Reference==&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Copyright=&lt;br /&gt;
This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited.&lt;br /&gt;
&lt;br /&gt;
{{Template:Student Image}}&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316098</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316098"/>
		<updated>2017-10-25T17:47:52Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence key historical discoveries, current research and animal models will be discussed. Towards the end of the page there are future questions listed on future investigations involving the cerebellum and the abnormalities from an affected cerebellum are also highlighted. Terms that may be difficult to understand have also been identified and defined.&lt;br /&gt;
&lt;br /&gt;
The following video provides a brief overview on the cerebellum which will be further discussed on the page:&lt;br /&gt;
&amp;lt;html5media height=&amp;quot;315&amp;quot; width=&amp;quot;560&amp;quot;&amp;gt;https://www.youtube.com/watch?v=Fir-v6EoZNE&amp;lt;/html5media&amp;gt; &amp;lt;ref&amp;gt; 2-Minute Neuroscience on Cerebellum. (2015). Retrieved October 25, 2017, from https://www.youtube.com/watch?v=Fir-v6EoZNE &amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;File:CerebellumDiv.png. (2016, December 15). Wikimedia Commons, the free media repository. Retrieved 12:48, October 24, 2017 from https://commons.wikimedia.org/w/index.php?title=File:CerebellumDiv.png&amp;amp;oldid=226277429.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;400&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;1100&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 5:''' (Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 6:''' (Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Developmental Weeks=&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
|&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
|  [[File:Stage9 dorsal.jpg|200px|thumb|'''Figure 7:''' Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|'''Figure 8: '''Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb|'''Figure 9:''' Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|'''Figure 10:''' Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|'''Figure 11:''' Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|'''Figure 12:''' Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
[[File:Second Trimester Cerebellum.jpeg|200px|thumb|'''Figure 13:''' Inferior image of a fetal cerebellum at second trimester]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development==&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|'''Figure 14:''' Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum. There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
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==Cerebellum Development==&lt;br /&gt;
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[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 15:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 16:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
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===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers; layers are shown in Figure 15. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
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The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
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The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
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==Cellular Migration==&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
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[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
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'''Figure 17:''' Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 18:''' SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===Proliferation in the EGL===&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP). &lt;br /&gt;
===Exit from the EGL===&lt;br /&gt;
BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
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[[File:Reelin signalling.jpg|300px|thumb|'''Figure 19:''' Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;Zhang, G., Assadi, A. H., McNeil, R. S., Beffert, U., Wynshaw-Boris, A., Herz, J., . . . D'Arcangelo, G. (2007). The Pafah1b Complex Interacts with the Reelin Receptor VLDLR. PLoS ONE, 2(2), 252nd ser. doi:https://doi.org/10.1371/journal.pone.0000252&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===FGF and the Isthmus===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
===Reelin and purkinje cells===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
===Transcription factors===&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
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==Key Historical Discoveries==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Year'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;500&amp;quot; |&amp;lt;center&amp;gt;'''Discoverer''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;700&amp;quot; |&amp;lt;center&amp;gt;'''Description '''&amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1500s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Galen, Vesalius and Varolio&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Described the macroscopic anatomy of the cerebellum&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Late 1700s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Luigi Rolando, Pierre Flourens&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Provided experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Ernesto Lugaro&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | First defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Joseph Babinski and Gordon Holmes&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Mid 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt; Ramon y Cajal&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|220px|thumb|right|'''Figure 20:''' Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] &lt;br /&gt;
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Refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed. &lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1880s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Olof Larsell&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1960s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;John Eccles and Janos Szentágothai&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Pieced together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
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=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
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==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 21:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
[[File:Zebrafish.jpg|210px|thumb|right|'''Figure 22:''' Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;220&amp;quot;| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|220px|thumb|center|'''Figure 23:''' Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|220px|thumb|center|'''Figure 24:''' Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|220px|thumb|center|'''Figure 25:''' Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|220px|thumb|center|'''Figure 26:''' Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Current Research= &lt;br /&gt;
==Emotional memory in depression==&lt;br /&gt;
Past investigations have concluded that damage to the posterior lobule of the cerebellum can cause individuals to show changes in manner or emotional instability, similar to a degree of depression or psychosis, without an outward cerebellar motor syndrome&amp;lt;ref name=&amp;quot;PMID16434422&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16434422&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is highly suggestive of the cerebellum's role in emotional memory despite its involvement with motor control. Patients with Major Depressive Disorder (MDD) display a tendency to only selectively recall aspects of scenarios that match their moods, conforming with the &amp;quot;mood-congruent memory (MCM)&amp;quot; theory &amp;lt;ref&amp;gt;Gilligan S. G., &amp;amp; Bower G. H. (1983). Reminding and mood‐congruent memory. Bulletin of the Psychonomic Society, 21, 431–434)&amp;lt;/ref&amp;gt;. This study was undertaken with that principle in mind, and investigated the depth of cerebellar involvement in emotional memory in depression. A link between the volume and density of cerebellar gray matter with measurements of emotional memory was hypothesised. &lt;br /&gt;
&lt;br /&gt;
The experiment was conducted between patients with Major Depressive Disorder (MDD) and healthy controls (HCs)&amp;lt;ref name=”PMID5516611”&amp;gt;&amp;lt;pubmed&amp;gt;5516611&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Patients with MDD displayed an atrophy in both gray matter and white matter, most severely in the posterior lobule. There was a significant impairment in emotional memory and decreased volume of the cerebellum in both anterior and posterior lobules. There was marked abnormalities in cortical density, but only a reduction in volume was found to be associated with decreased emotional memory. The severity of depressive symptoms correlated with both volume and density reduction in the grey matter. &lt;br /&gt;
The posterior, anterior and flocculonodular lobes of patients with MDD displayed marked structural differences from the healthy controls, and a functional connectivity between lobules VI and VII of the cerebellum and the cerebrum could indicate that the decreased density in the lobules of MDD patients contributes to alterations in this connectivity. The flocculonodular lobe is especially implicated in MDD. The lobe is associated with vestibular regulation;  Soza and Aviles (2007)&amp;lt;ref name=”PMID17074443”&amp;gt;&amp;lt;pubmed&amp;gt;17074443&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; found that patients who experienced vestibular vertigo also experienced depressive symptoms. This study also determined that patients who experienced depression also experienced bouts of dizziness. Thus, an unprecedentedly widespread area of the cerebellum is displayed to be connected with emotional memory, in particular, with positive or negative memory retention and could lead towards a cure for depression. &lt;br /&gt;
&lt;br /&gt;
==Dystonia==&lt;br /&gt;
This investigation into a potential link between dystonia -a disorder where muscles contract involuntarily- and the cerebellum attempts to delineate its pathophysiological role in the disease &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;5429509&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; . The main concern is that the etiology of dystonia appears to be extremely varied, and as such, unpredictable. There is no significant neural degeneration, but in secondary cases there may be structural lesions present in tissue which could be areas of pathophysiology in dystonia &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;27173653&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Dystonia may manifest itself in almost any body part, indicating that the neural area responsible most likely must not be very specific. This in combination with the involuntary nature of dystonia seems to indicate that the cerebellum is the more than likely involved in the disease. &lt;br /&gt;
&lt;br /&gt;
Basal ganglia abnormalities are hinted to be a causative agent in dystonia.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;9679773&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The gap in the knowledge of the true interactions between basal ganglia and the cerebellum with regards to dystonia have led to a hypothesis; that the difference in basal ganglia malfunctioning versus abnormal interaction between the ganglia and the cerebellum could reflect the heterogenous pathophysiology of dystonia; either primary or secondary. Some experimental evidence currently available implies that cerebellar dysfunction could affect the topographic distribution of the symptoms of dystonia, and therefore further research is warranted to investigate the full depth of basal ganglia involvement in the disease. &lt;br /&gt;
&lt;br /&gt;
==Adaptation to Delayed Action Effects==&lt;br /&gt;
Sensory attenuation refers to when individuals filters unnecessary information. When there is a perturbation between actions and the following-sound, the sensory attenuation is reduced &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
An example of this is when there is a delay when an individual presses a button with sound immediately expected, but instead the sound is delayed. Sensory attenuation can be further described by the forward model theory. The forward model theory suggests that predictions for sensory consequences (for example, sound that is heard) are made simultaneously with the motor movement&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Predictions and real sensory input (what really happens), after the sound delay is conducted, are compared in the model. If the prediction and real sensory input do not matchup, sensory attenuation is observed. The prediction errors are then relayed to other brain areas for further processing&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
The process of sensory attenuation usually re-emerges after the disruption to the normal mechanism &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The re-emerging of this is a process of either correcting previous predictions or updating initial forward models to minimise prediction errors. The cerebellum is currently being researched on how it plays an important role in updating the forward model within the brain&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. One investigation seeks to find evidence on the involvement of the cerebellum in learning to predict the unexpected delays. This investigation has found that low-frequency activity in the cerebellum, prior to the stimulation, plays a key role in adapting to the delayed stimulus &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
==Addiction==&lt;br /&gt;
The cerebellum has only recently been suspected to be involved in addictive behaviour, as some arguments provided for the initiation of research into the cerebellar role on addiction&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26602022&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum is shown to be intrinsically linked with dopamine release and reception&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;16451810&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;; with dopamine being the main hormone on which addiction is predicated, it is likely that the cerebellum could influence the response to the addictive stimuli. It has also been established that addictive drugs cause specific molecular mechanisms, changes in synapse plasticity&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;10224304&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, and influence intracellular transduction pathways as well as gene expression in the cerebellum&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25262781&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The specificity of the drugs in targeting the cerebellum could highlight the link between the affected organ and addictive behaviour. Addictive drugs such as cocaine have been demonstrated to produce a behavioral sensitivity in mice, and an associated change in cerebellar plasticity. The change of the morphology of Purkinje cells and synaptic terminals in the mice most likely contributed to the difference in reception of the drug&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25619460&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, this link has not yet been fully investigated. &lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Although there are numerous articles and ongoing research on the cerebellum, there are still investigations yet to be performed. Some questions that could be answered in future research include:&lt;br /&gt;
*Is the cerebellum size related to human intelligence?&lt;br /&gt;
*Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
*What changes in cerebellum development lead to the social impairments seen in those with Autism Spectrum Disorder?&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;28150911&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
*'''Perturbation''' –  (In the context of the Current Research) alternation to the normal mechanism that would happen in response to a stimulation &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316090</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316090"/>
		<updated>2017-10-25T16:46:53Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence key historical discoveries, current research and animal models will be discussed. Towards the end of the page there are future questions listed on future investigations involving the cerebellum and the abnormalities from an affected cerebellum are also highlighted. Terms that may be difficult to understand have also been identified and defined.&lt;br /&gt;
&lt;br /&gt;
The following video provides a brief overview on the cerebellum which will be further discussed on the page:&lt;br /&gt;
&amp;lt;html5media height=&amp;quot;315&amp;quot; width=&amp;quot;560&amp;quot;&amp;gt;https://www.youtube.com/watch?v=Fir-v6EoZNE&amp;lt;/html5media&amp;gt; &amp;lt;ref&amp;gt; 2-Minute Neuroscience on Cerebellum. (2015). Retrieved October 25, 2017, from https://www.youtube.com/watch?v=Fir-v6EoZNE &amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;File:CerebellumDiv.png. (2016, December 15). Wikimedia Commons, the free media repository. Retrieved 12:48, October 24, 2017 from https://commons.wikimedia.org/w/index.php?title=File:CerebellumDiv.png&amp;amp;oldid=226277429.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;400&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;1100&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 5:''' (Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 6:''' (Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Developmental Weeks=&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
|&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
|  [[File:Stage9 dorsal.jpg|200px|thumb|'''Figure 7:''' Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|'''Figure 8: '''Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb|'''Figure 9:''' Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|'''Figure 10:''' Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|'''Figure 11:''' Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|'''Figure 12:''' Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
[[File:Second Trimester Cerebellum.jpeg|200px|thumb|'''Figure 13:''' Inferior image of a fetal cerebellum at second trimester]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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&lt;br /&gt;
==Neural Development==&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|'''Figure 14:''' Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum. There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 15:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 16:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers; layers are shown in Figure 15. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 17:''' Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 18:''' SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===Proliferation in the EGL===&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP). &lt;br /&gt;
===Exit from the EGL===&lt;br /&gt;
BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|300px|thumb|'''Figure 19:''' Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;Zhang, G., Assadi, A. H., McNeil, R. S., Beffert, U., Wynshaw-Boris, A., Herz, J., . . . D'Arcangelo, G. (2007). The Pafah1b Complex Interacts with the Reelin Receptor VLDLR. PLoS ONE, 2(2), 252nd ser. doi:https://doi.org/10.1371/journal.pone.0000252&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===FGF and the Isthmus===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
===Reelin and purkinje cells===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
===Transcription factors===&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
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&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Year'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;500&amp;quot; |&amp;lt;center&amp;gt;'''Discoverer''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;700&amp;quot; |&amp;lt;center&amp;gt;'''Description '''&amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1500s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Galen, Vesalius and Varolio&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Described the macroscopic anatomy of the cerebellum&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Late 1700s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Luigi Rolando, Pierre Flourens&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Provided experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Ernesto Lugaro&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | First defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Joseph Babinski and Gordon Holmes&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Mid 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt; Ramon y Cajal&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|220px|thumb|right|'''Figure 20:''' Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] &lt;br /&gt;
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Refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed. &lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1880s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Olof Larsell&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1960s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;John Eccles and Janos Szentágothai&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Pieced together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
|}&lt;br /&gt;
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&lt;br /&gt;
=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 21:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
[[File:Zebrafish.jpg|210px|thumb|right|'''Figure 22:''' Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;220&amp;quot;| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|220px|thumb|center|'''Figure 23:''' Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|220px|thumb|center|'''Figure 24:''' Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|220px|thumb|center|'''Figure 25:''' Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|220px|thumb|center|'''Figure 26:''' Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Current Research= &lt;br /&gt;
==Emotional memory in depression==&lt;br /&gt;
Past investigations have concluded that damage to the posterior lobule of the cerebellum can cause individuals to show changes in manner or emotional instability, similar to a degree of depression or psychosis, without an outward cerebellar motor syndrome&amp;lt;ref name=&amp;quot;PMID16434422&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16434422&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is highly suggestive of the cerebellum's role in emotional memory despite its involvement with motor control. Patients with Major Depressive Disorder (MDD) display a tendency to only selectively recall aspects of scenarios that match their moods, conforming with the &amp;quot;mood-congruent memory (MCM)&amp;quot; theory &amp;lt;ref&amp;gt;Gilligan S. G., &amp;amp; Bower G. H. (1983). Reminding and mood‐congruent memory. Bulletin of the Psychonomic Society, 21, 431–434)&amp;lt;/ref&amp;gt;. This study was undertaken with that principle in mind, and investigated the depth of cerebellar involvement in emotional memory in depression. A link between the volume and density of cerebellar gray matter with measurements of emotional memory was hypothesised. &lt;br /&gt;
&lt;br /&gt;
The experiment was conducted between patients with Major Depressive Disorder (MDD) and healthy controls (HCs)&amp;lt;ref name=”PMID5516611”&amp;gt;&amp;lt;pubmed&amp;gt;5516611&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Patients with MDD displayed an atrophy in both gray matter and white matter, most severely in the posterior lobule. There was a significant impairment in emotional memory and decreased volume of the cerebellum in both anterior and posterior lobules. There was marked abnormalities in cortical density, but only a reduction in volume was found to be associated with decreased emotional memory. The severity of depressive symptoms correlated with both volume and density reduction in the grey matter. &lt;br /&gt;
The posterior, anterior and flocculonodular lobes of patients with MDD displayed marked structural differences from the healthy controls, and a functional connectivity between lobules VI and VII of the cerebellum and the cerebrum could indicate that the decreased density in the lobules of MDD patients contributes to alterations in this connectivity. The flocculonodular lobe is especially implicated in MDD. The lobe is associated with vestibular regulation;  Soza and Aviles (2007)&amp;lt;ref name=”PMID17074443”&amp;gt;&amp;lt;pubmed&amp;gt;17074443&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; found that patients who experienced vestibular vertigo also experienced depressive symptoms. This study also determined that patients who experienced depression also experienced bouts of dizziness. Thus, an unprecedentedly widespread area of the cerebellum is displayed to be connected with emotional memory, in particular, with positive or negative memory retention and could lead towards a cure for depression. &lt;br /&gt;
&lt;br /&gt;
==Dystonia==&lt;br /&gt;
This investigation into a potential link between dystonia -a disorder where muscles contract involuntarily- and the cerebellum attempts to delineate its pathophysiological role in the disease &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;5429509&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; . The main concern is that the etiology of dystonia appears to be extremely varied, and as such, unpredictable. There is no significant neural degeneration, but in secondary cases there may be structural lesions present in tissue which could be areas of pathophysiology in dystonia &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;27173653&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Dystonia may manifest itself in almost any body part, indicating that the neural area responsible most likely must not be very specific. This in combination with the involuntary nature of dystonia seems to indicate that the cerebellum is the more than likely involved in the disease. &lt;br /&gt;
&lt;br /&gt;
Basal ganglia abnormalities are hinted to be a causative agent in dystonia.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;9679773&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The gap in the knowledge of the true interactions between basal ganglia and the cerebellum with regards to dystonia have led to a hypothesis; that the difference in basal ganglia malfunctioning versus abnormal interaction between the ganglia and the cerebellum could reflect the heterogenous pathophysiology of dystonia; either primary or secondary. Some experimental evidence currently available implies that cerebellar dysfunction could affect the topographic distribution of the symptoms of dystonia, and therefore further research is warranted to investigate the full depth of basal ganglia involvement in the disease. &lt;br /&gt;
&lt;br /&gt;
==Adaptation to Delayed Action Effects==&lt;br /&gt;
Sensory attenuation refers to when individuals filters unnecessary information. When there is a perturbation between actions and the following-sound, the sensory attenuation is reduced &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
An example of this is when there is a delay when an individual presses a button with sound immediately expected, but instead the sound is delayed. Sensory attenuation can be further described by the forward model theory. The forward model theory suggests that predictions for sensory consequences (for example, sound that is heard) are made simultaneously with the motor movement&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Predictions and real sensory input (what really happens), after the sound delay is conducted, are compared in the model. If the prediction and real sensory input do not matchup, sensory attenuation is observed. The prediction errors are then relayed to other brain areas for further processing&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
The process of sensory attenuation usually re-emerges after the disruption to the normal mechanism &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The re-emerging of this is a process of either correcting previous predictions or updating initial forward models to minimise prediction errors. The cerebellum is currently being researched on how it plays an important role in updating the forward model within the brain&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. One investigation seeks to find evidence on the involvement of the cerebellum in learning to predict the unexpected delays. This investigation has found that low-frequency activity in the cerebellum, prior to the stimulation, plays a key role in adapting to the delayed stimulus &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
==Addiction==&lt;br /&gt;
http://www.sciencedirect.com/science/article/pii/S0149763415002754?via%3Dihub &lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Although there are numerous articles and ongoing research on the cerebellum, there are still investigations yet to be performed. Some questions that could be answered in future research include:&lt;br /&gt;
*Is the cerebellum size related to human intelligence?&lt;br /&gt;
*Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
*What changes in cerebellum development lead to the social impairments seen in those with Autism Spectrum Disorder?&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;28150911&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
*'''Perturbation''' –  (In the context of the Current Research) alternation to the normal mechanism that would happen in response to a stimulation &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
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{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
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		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316088</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316088"/>
		<updated>2017-10-25T16:41:02Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence key historical discoveries, current research and animal models will be discussed. Towards the end of the page there are future questions listed on future investigations involving the cerebellum and the abnormalities from an affected cerebellum are also highlighted. Terms that may be difficult to understand have also been identified and defined.&lt;br /&gt;
&lt;br /&gt;
The following video provides a brief overview on the cerebellum which will be further discussed on the page:&lt;br /&gt;
&amp;lt;html5media height=&amp;quot;315&amp;quot; width=&amp;quot;560&amp;quot;&amp;gt;https://www.youtube.com/watch?v=Fir-v6EoZNE&amp;lt;/html5media&amp;gt; &amp;lt;ref&amp;gt; 2-Minute Neuroscience on Cerebellum. (2015). Retrieved October 25, 2017, from https://www.youtube.com/watch?v=Fir-v6EoZNE &amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;File:CerebellumDiv.png. (2016, December 15). Wikimedia Commons, the free media repository. Retrieved 12:48, October 24, 2017 from https://commons.wikimedia.org/w/index.php?title=File:CerebellumDiv.png&amp;amp;oldid=226277429.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
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==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;400&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;1100&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 5:''' (Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 6:''' (Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Developmental Weeks=&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
|&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
|  [[File:Stage9 dorsal.jpg|200px|thumb|'''Figure 7:''' Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|'''Figure 8: '''Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb|'''Figure 9:''' Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|'''Figure 10:''' Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|'''Figure 11:''' Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|'''Figure 12:''' Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
[[File:Second Trimester Cerebellum.jpeg|200px|thumb|'''Figure 13:''' Inferior image of a fetal cerebellum at second trimester]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development==&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|'''Figure 14:''' Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum. There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 15:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 16:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers; layers are shown in Figure 15. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 17:''' Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 18:''' SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===Proliferation in the EGL===&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP). &lt;br /&gt;
===Exit from the EGL===&lt;br /&gt;
BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|300px|thumb|'''Figure 19:''' Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;Zhang, G., Assadi, A. H., McNeil, R. S., Beffert, U., Wynshaw-Boris, A., Herz, J., . . . D'Arcangelo, G. (2007). The Pafah1b Complex Interacts with the Reelin Receptor VLDLR. PLoS ONE, 2(2), 252nd ser. doi:https://doi.org/10.1371/journal.pone.0000252&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===FGF and the Isthmus===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
===Reelin and purkinje cells===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
===Transcription factors===&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
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==Key Historical Discoveries==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Year'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;500&amp;quot; |&amp;lt;center&amp;gt;'''Discoverer''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;700&amp;quot; |&amp;lt;center&amp;gt;'''Description '''&amp;lt;/center&amp;gt;&lt;br /&gt;
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| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1500s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Galen, Vesalius and Varolio&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Described the macroscopic anatomy of the cerebellum&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Late 1700s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Luigi Rolando, Pierre Flourens&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Provided experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Ernesto Lugaro&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | First defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Joseph Babinski and Gordon Holmes&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Mid 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt; Ramon y Cajal&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|220px|thumb|right|'''Figure 20:''' Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] &lt;br /&gt;
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Refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed. &lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1880s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Olof Larsell&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1960s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;John Eccles and Janos Szentágothai&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Pieced together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
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=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
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==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 21:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
[[File:Zebrafish.jpg|210px|thumb|right|'''Figure 22:''' Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
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=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;220&amp;quot;| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|220px|thumb|center|'''Figure 23:''' Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|220px|thumb|center|'''Figure 24:''' Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|220px|thumb|center|'''Figure 25:''' Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|220px|thumb|center|'''Figure 26:''' Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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=Current Research= &lt;br /&gt;
==Emotional memory in depression==&lt;br /&gt;
Past investigations have concluded that damage to the posterior lobule of the cerebellum can cause individuals to show changes in manner or emotional instability, similar to a degree of depression or psychosis, without an outward cerebellar motor syndrome&amp;lt;ref name=&amp;quot;PMID16434422&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16434422&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is highly suggestive of the cerebellum's role in emotional memory despite its involvement with motor control. Patients with Major Depressive Disorder (MDD) display a tendency to only selectively recall aspects of scenarios that match their moods, conforming with the &amp;quot;mood-congruent memory (MCM)&amp;quot; theory &amp;lt;ref&amp;gt;Gilligan S. G., &amp;amp; Bower G. H. (1983). Reminding and mood‐congruent memory. Bulletin of the Psychonomic Society, 21, 431–434)&amp;lt;/ref&amp;gt;. This study was undertaken with that principle in mind, and investigated the depth of cerebellar involvement in emotional memory in depression. A link between the volume and density of cerebellar gray matter with measurements of emotional memory was hypothesised. &lt;br /&gt;
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The experiment was conducted between patients with Major Depressive Disorder (MDD) and healthy controls (HCs)&amp;lt;ref name=”PMID5516611”&amp;gt;&amp;lt;pubmed&amp;gt;5516611&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Patients with MDD displayed an atrophy in both gray matter and white matter, most severely in the posterior lobule. There was a significant impairment in emotional memory and decreased volume of the cerebellum in both anterior and posterior lobules. There was marked abnormalities in cortical density, but only a reduction in volume was found to be associated with decreased emotional memory. The severity of depressive symptoms correlated with both volume and density reduction in the grey matter. &lt;br /&gt;
The posterior, anterior and flocculonodular lobes of patients with MDD displayed marked structural differences from the healthy controls, and a functional connectivity between lobules VI and VII of the cerebellum and the cerebrum could indicate that the decreased density in the lobules of MDD patients contributes to alterations in this connectivity. The flocculonodular lobe is especially implicated in MDD. The lobe is associated with vestibular regulation;  Soza and Aviles (2007)&amp;lt;ref name=”PMID17074443”&amp;gt;&amp;lt;pubmed&amp;gt;17074443&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; found that patients who experienced vestibular vertigo also experienced depressive symptoms. This study also determined that patients who experienced depression also experienced bouts of dizziness. Thus, an unprecedentedly widespread area of the cerebellum is displayed to be connected with emotional memory, in particular, with positive or negative memory retention and could lead towards a cure for depression. &lt;br /&gt;
&lt;br /&gt;
==Dystonia==&lt;br /&gt;
This investigation into a potential link between dystonia -a disorder where muscles contract involuntarily- and the cerebellum attempts to delineate its pathophysiological role in the disease &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;5429509&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; . The main concern is that the etiology of dystonia appears to be extremely varied, and as such, unpredictable. There is no significant neural degeneration, but in secondary cases there may be structural lesions present in tissue which could be areas of pathophysiology in dystonia &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;27173653&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Dystonia may manifest itself in almost any body part, indicating that the neural area responsible most likely must not be very specific. This in combination with the involuntary nature of dystonia seems to indicate that the cerebellum is the more than likely involved in the disease. &lt;br /&gt;
&lt;br /&gt;
Basal ganglia abnormalities are hinted to be a causative agent in dystonia.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;9679773&amp;lt;/pubmed&amp;gt;&amp;lt;ref&amp;gt;. The gap in the knowledge of the true interactions between basal ganglia and the cerebellum with regards to dystonia have led to a hypothesis; that the difference in basal ganglia malfunctioning versus abnormal interaction between the ganglia and the cerebellum could reflect the heterogenous pathophysiology of dystonia; either primary or secondary. Some experimental evidence currently available implies that cerebellar dysfunction could affect the topographic distribution of the symptoms of dystonia, and therefore further research is warranted to investigate the full depth of basal ganglia involvement in the disease. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Adaptation to Delayed Action Effects==&lt;br /&gt;
Sensory attenuation refers to when individuals filters unnecessary information. When there is a perturbation between actions and the following-sound, the sensory attenuation is reduced &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
An example of this is when there is a delay when an individual presses a button with sound immediately expected, but instead the sound is delayed. Sensory attenuation can be further described by the forward model theory. The forward model theory suggests that predictions for sensory consequences (for example, sound that is heard) are made simultaneously with the motor movement&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Predictions and real sensory input (what really happens), after the sound delay is conducted, are compared in the model. If the prediction and real sensory input do not matchup, sensory attenuation is observed. The prediction errors are then relayed to other brain areas for further processing&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
The process of sensory attenuation usually re-emerges after the disruption to the normal mechanism &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The re-emerging of this is a process of either correcting previous predictions or updating initial forward models to minimise prediction errors. The cerebellum is currently being researched on how it plays an important role in updating the forward model within the brain&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. One investigation seeks to find evidence on the involvement of the cerebellum in learning to predict the unexpected delays. This investigation has found that low-frequency activity in the cerebellum, prior to the stimulation, plays a key role in adapting to the delayed stimulus &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
==Addiction==&lt;br /&gt;
http://www.sciencedirect.com/science/article/pii/S0149763415002754?via%3Dihub &lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Although there are numerous articles and ongoing research on the cerebellum, there are still investigations yet to be performed. Some questions that could be answered in future research include:&lt;br /&gt;
*Is the cerebellum size related to human intelligence?&lt;br /&gt;
*Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
*What changes in cerebellum development lead to the social impairments seen in those with Autism Spectrum Disorder?&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;28150911&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
*'''Perturbation''' –  (In the context of the Current Research) alternation to the normal mechanism that would happen in response to a stimulation &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316086</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316086"/>
		<updated>2017-10-25T16:17:16Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence key historical discoveries, current research and animal models will be discussed. Towards the end of the page there are future questions listed on future investigations involving the cerebellum and the abnormalities from an affected cerebellum are also highlighted. Terms that may be difficult to understand have also been identified and defined.&lt;br /&gt;
&lt;br /&gt;
The following video provides a brief overview on the cerebellum which will be further discussed on the page:&lt;br /&gt;
&amp;lt;html5media height=&amp;quot;315&amp;quot; width=&amp;quot;560&amp;quot;&amp;gt;https://www.youtube.com/watch?v=Fir-v6EoZNE&amp;lt;/html5media&amp;gt; &amp;lt;ref&amp;gt; 2-Minute Neuroscience on Cerebellum. (2015). Retrieved October 25, 2017, from https://www.youtube.com/watch?v=Fir-v6EoZNE &amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;File:CerebellumDiv.png. (2016, December 15). Wikimedia Commons, the free media repository. Retrieved 12:48, October 24, 2017 from https://commons.wikimedia.org/w/index.php?title=File:CerebellumDiv.png&amp;amp;oldid=226277429.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;400&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;1100&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 5:''' (Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 6:''' (Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Developmental Weeks=&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
|&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
|  [[File:Stage9 dorsal.jpg|200px|thumb|'''Figure 7:''' Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|'''Figure 8: '''Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb|'''Figure 9:''' Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|'''Figure 10:''' Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|'''Figure 11:''' Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|'''Figure 12:''' Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
[[File:Second Trimester Cerebellum.jpeg|200px|thumb|'''Figure 13:''' Inferior image of a fetal cerebellum at second trimester]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development==&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|'''Figure 14:''' Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum. There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 15:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 16:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers; layers are shown in Figure 15. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 17:''' Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 18:''' SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===Proliferation in the EGL===&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP). &lt;br /&gt;
===Exit from the EGL===&lt;br /&gt;
BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|300px|thumb|'''Figure 19:''' Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;Zhang, G., Assadi, A. H., McNeil, R. S., Beffert, U., Wynshaw-Boris, A., Herz, J., . . . D'Arcangelo, G. (2007). The Pafah1b Complex Interacts with the Reelin Receptor VLDLR. PLoS ONE, 2(2), 252nd ser. doi:https://doi.org/10.1371/journal.pone.0000252&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===FGF and the Isthmus===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
===Reelin and purkinje cells===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
===Transcription factors===&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Year'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;500&amp;quot; |&amp;lt;center&amp;gt;'''Discoverer''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;700&amp;quot; |&amp;lt;center&amp;gt;'''Description '''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1500s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Galen, Vesalius and Varolio&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Described the macroscopic anatomy of the cerebellum&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Late 1700s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Luigi Rolando, Pierre Flourens&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Provided experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Ernesto Lugaro&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | First defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Joseph Babinski and Gordon Holmes&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Mid 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt; Ramon y Cajal&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|220px|thumb|right|'''Figure 20:''' Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] &lt;br /&gt;
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Refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed. &lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1880s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Olof Larsell&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1960s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;John Eccles and Janos Szentágothai&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Pieced together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 21:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
[[File:Zebrafish.jpg|210px|thumb|right|'''Figure 22:''' Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;220&amp;quot;| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|220px|thumb|center|'''Figure 23:''' Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|220px|thumb|center|'''Figure 24:''' Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|220px|thumb|center|'''Figure 25:''' Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|220px|thumb|center|'''Figure 26:''' Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Current Research= &lt;br /&gt;
==Emotional memory in depression==&lt;br /&gt;
Past investigations have concluded that damage to the posterior lobule of the cerebellum can cause individuals to show changes in manner or emotional instability, similar to a degree of depression or psychosis, without an outward cerebellar motor syndrome&amp;lt;ref name=&amp;quot;PMID16434422&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16434422&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is highly suggestive of the cerebellum's role in emotional memory despite its involvement with motor control. Patients with Major Depressive Disorder (MDD) display a tendency to only selectively recall aspects of scenarios that match their moods, conforming with the &amp;quot;mood-congruent memory (MCM)&amp;quot; theory &amp;lt;ref&amp;gt;Gilligan S. G., &amp;amp; Bower G. H. (1983). Reminding and mood‐congruent memory. Bulletin of the Psychonomic Society, 21, 431–434)&amp;lt;/ref&amp;gt;. This study was undertaken with that principle in mind, and investigated the depth of cerebellar involvement in emotional memory in depression. A link between the volume and density of cerebellar gray matter with measurements of emotional memory was hypothesised. &lt;br /&gt;
&lt;br /&gt;
The experiment was conducted between patients with Major Depressive Disorder (MDD) and healthy controls (HCs)&amp;lt;ref name=”PMID5516611”&amp;gt;&amp;lt;pubmed&amp;gt;5516611&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Patients with MDD displayed an atrophy in both gray matter and white matter, most severely in the posterior lobule. There was a significant impairment in emotional memory and decreased volume of the cerebellum in both anterior and posterior lobules. There was marked abnormalities in cortical density, but only a reduction in volume was found to be associated with decreased emotional memory. The severity of depressive symptoms correlated with both volume and density reduction in the grey matter. &lt;br /&gt;
The posterior, anterior and flocculonodular lobes of patients with MDD displayed marked structural differences from the healthy controls, and a functional connectivity between lobules VI and VII of the cerebellum and the cerebrum could indicate that the decreased density in the lobules of MDD patients contributes to alterations in this connectivity. The flocculonodular lobe is especially implicated in MDD. The lobe is associated with vestibular regulation;  Soza and Aviles (2007)&amp;lt;ref name=”PMID17074443”&amp;gt;&amp;lt;pubmed&amp;gt;17074443&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; found that patients who experienced vestibular vertigo also experienced depressive symptoms. This study also determined that patients who experienced depression also experienced bouts of dizziness. Thus, an unprecedentedly widespread area of the cerebellum is displayed to be connected with emotional memory, in particular, with positive or negative memory retention and could lead towards a cure for depression. &lt;br /&gt;
&lt;br /&gt;
==Dystonia==&lt;br /&gt;
This investigation into a potential link between dystonia -a disorder where muscles contract involuntarily- and the cerebellum attempts to delineate its pathophysiological role in the disease &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;5429509&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; . The main concern is that the etiology of dystonia appears to be extremely varied, and as such, unpredictable. There is no significant neural degeneration, but in secondary cases there may be structural lesions present in tissue which could be areas of pathophysiology in dystonia &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;27173653&amp;lt;/pubmed&amp;gt;&amp;lt;ref&amp;gt;. Dystonia may manifest itself in almost any body part, indicating that the neural area responsible most likely must not be very specific. This in combination with the involuntary nature of dystonia seems to indicate that the cerebellum is the more than likely involved in the disease. &lt;br /&gt;
&lt;br /&gt;
Basal ganglia abnormalities are hinted to be a causative agent in dystonia.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;9679773&amp;lt;/pubmed&amp;gt;&amp;lt;ref&amp;gt;. The gap in the knowledge of the true interactions between basal ganglia and the cerebellum with regards to dystonia have led to a hypothesis; that the difference in basal ganglia malfunctioning versus abnormal interaction between the ganglia and the cerebellum could reflect the heterogenous pathophysiology of dystonia; either primary or secondary. Some experimental evidence currently available implies that cerebellar dysfunction could affect the topographic distribution of the symptoms of dystonia, and therefore further research is warranted to investigate the full depth of basal ganglia involvement in the disease. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Adaptation to Delayed Action Effects==&lt;br /&gt;
Sensory attenuation refers to when individuals filters unnecessary information. When there is a perturbation between actions and the following-sound, the sensory attenuation is reduced &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
An example of this is when there is a delay when an individual presses a button with sound immediately expected, but instead the sound is delayed. Sensory attenuation can be further described by the forward model theory. The forward model theory suggests that predictions for sensory consequences (for example, sound that is heard) are made simultaneously with the motor movement&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Predictions and real sensory input (what really happens), after the sound delay is conducted, are compared in the model. If the prediction and real sensory input do not matchup, sensory attenuation is observed. The prediction errors are then relayed to other brain areas for further processing&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
The process of sensory attenuation usually re-emerges after the disruption to the normal mechanism &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The re-emerging of this is a process of either correcting previous predictions or updating initial forward models to minimise prediction errors. The cerebellum is currently being researched on how it plays an important role in updating the forward model within the brain&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. One investigation seeks to find evidence on the involvement of the cerebellum in learning to predict the unexpected delays. This investigation has found that low-frequency activity in the cerebellum, prior to the stimulation, plays a key role in adapting to the delayed stimulus &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
==Addiction==&lt;br /&gt;
http://www.sciencedirect.com/science/article/pii/S0149763415002754?via%3Dihub &lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Although there are numerous articles and ongoing research on the cerebellum, there are still investigations yet to be performed. Some questions that could be answered in future research include:&lt;br /&gt;
*Is the cerebellum size related to human intelligence?&lt;br /&gt;
*Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
*What changes in cerebellum development lead to the social impairments seen in those with Autism Spectrum Disorder?&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;28150911&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
*'''Perturbation''' –  (In the context of the Current Research) alternation to the normal mechanism that would happen in response to a stimulation &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316074</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=316074"/>
		<updated>2017-10-25T15:28:10Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence key historical discoveries, current research and animal models will be discussed. Towards the end of the page there are future questions listed on future investigations involving the cerebellum and the abnormalities from an affected cerebellum are also highlighted. Terms that may be difficult to understand have also been identified and defined.&lt;br /&gt;
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The following video provides a brief overview on the cerebellum which will be further discussed on the page:&lt;br /&gt;
&amp;lt;html5media height=&amp;quot;315&amp;quot; width=&amp;quot;560&amp;quot;&amp;gt;https://www.youtube.com/watch?v=Fir-v6EoZNE&amp;lt;/html5media&amp;gt; &amp;lt;ref&amp;gt; 2-Minute Neuroscience on Cerebellum. (2015). Retrieved October 25, 2017, from https://www.youtube.com/watch?v=Fir-v6EoZNE &amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Basic Anatomy of the Cerebellum=&lt;br /&gt;
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The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
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[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
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'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
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'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;File:CerebellumDiv.png. (2016, December 15). Wikimedia Commons, the free media repository. Retrieved 12:48, October 24, 2017 from https://commons.wikimedia.org/w/index.php?title=File:CerebellumDiv.png&amp;amp;oldid=226277429.&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
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==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
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There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Cerebellar Nuclei===&lt;br /&gt;
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{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;400&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;1100&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
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| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
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&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain.png|500px]]&lt;br /&gt;
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'''Figure 5:''' (Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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'''Figure 6:''' (Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
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*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
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*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
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*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
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==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
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The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Cerebellum Developmental Weeks=&lt;br /&gt;
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===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
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|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
|&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
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| &amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
|  [[File:Stage9 dorsal.jpg|200px|thumb|'''Figure 7:''' Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|'''Figure 8: '''Late stages of neurulation]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb|'''Figure 9:''' Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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| &amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|'''Figure 10:''' Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
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| &amp;lt;center&amp;gt;'''Week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
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| &amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|'''Figure 11:''' Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|'''Figure 12:''' Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
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===Second Trimester===&lt;br /&gt;
[[File:Second Trimester Cerebellum.jpeg|200px|thumb|'''Figure 13:''' Inferior image of a fetal cerebellum at second trimester]]&lt;br /&gt;
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{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
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| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
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==Neural Development==&lt;br /&gt;
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[[File:2 day old embryo diagram.jpeg|200px|thumb|'''Figure 14:''' Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum. There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
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==Cerebellum Development==&lt;br /&gt;
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[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 15:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 16:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers; layers are shown in Figure 15. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 17:''' Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 18:''' SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===Proliferation in the EGL===&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP). &lt;br /&gt;
===Exit from the EGL===&lt;br /&gt;
BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|300px|thumb|'''Figure 19:''' Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;Zhang, G., Assadi, A. H., McNeil, R. S., Beffert, U., Wynshaw-Boris, A., Herz, J., . . . D'Arcangelo, G. (2007). The Pafah1b Complex Interacts with the Reelin Receptor VLDLR. PLoS ONE, 2(2), 252nd ser. doi:https://doi.org/10.1371/journal.pone.0000252&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===FGF and the Isthmus===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
===Reelin and purkinje cells===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
===Transcription factors===&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Year'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;500&amp;quot; |&amp;lt;center&amp;gt;'''Discoverer''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;700&amp;quot; |&amp;lt;center&amp;gt;'''Description '''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1500s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Galen, Vesalius and Varolio&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Described the macroscopic anatomy of the cerebellum&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Late 1700s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Luigi Rolando, Pierre Flourens&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Provided experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Ernesto Lugaro&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | First defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Joseph Babinski and Gordon Holmes&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Mid 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt; Ramon y Cajal&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|220px|thumb|right|'''Figure 20:''' Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] &lt;br /&gt;
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&lt;br /&gt;
Refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed. &lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1880s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Olof Larsell&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1960s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;John Eccles and Janos Szentágothai&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Pieced together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
|}&lt;br /&gt;
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&lt;br /&gt;
=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 21:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
[[File:Zebrafish.jpg|210px|thumb|right|'''Figure 22:''' Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;220&amp;quot;| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|220px|thumb|center|'''Figure 23:''' Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|220px|thumb|center|'''Figure 24:''' Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|220px|thumb|center|'''Figure 25:''' Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|220px|thumb|center|'''Figure 26:''' Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Current Research= &lt;br /&gt;
==Emotional memory in depression==&lt;br /&gt;
Past investigations have concluded that damage to the posterior lobule of the cerebellum can cause individuals to show changes in manner or emotional instability, similar to a degree of depression or psychosis, without an outward cerebellar motor syndrome&amp;lt;ref name=&amp;quot;PMID16434422&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16434422&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is highly suggestive of the cerebellum's role in emotional memory despite its involvement with motor control. Patients with Major Depressive Disorder (MDD) display a tendency to only selectively recall aspects of scenarios that match their moods, conforming with the &amp;quot;mood-congruent memory (MCM)&amp;quot; theory &amp;lt;ref&amp;gt;Gilligan S. G., &amp;amp; Bower G. H. (1983). Reminding and mood‐congruent memory. Bulletin of the Psychonomic Society, 21, 431–434)&amp;lt;/ref&amp;gt;. This study was undertaken with that principle in mind, and investigated the depth of cerebellar involvement in emotional memory in depression. A link between the volume and density of cerebellar gray matter with measurements of emotional memory was hypothesised. &lt;br /&gt;
&lt;br /&gt;
The experiment was conducted between patients with Major Depressive Disorder (MDD) and healthy controls (HCs)&amp;lt;ref name=”PMID5516611”&amp;gt;&amp;lt;pubmed&amp;gt;5516611&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Patients with MDD displayed an atrophy in both gray matter and white matter, most severely in the posterior lobule. There was a significant impairment in emotional memory and decreased volume of the cerebellum in both anterior and posterior lobules. There was marked abnormalities in cortical density, but only a reduction in volume was found to be associated with decreased emotional memory. The severity of depressive symptoms correlated with both volume and density reduction in the grey matter. &lt;br /&gt;
The posterior, anterior and flocculonodular lobes of patients with MDD displayed marked structural differences from the healthy controls, and a functional connectivity between lobules VI and VII of the cerebellum and the cerebrum could indicate that the decreased density in the lobules of MDD patients contributes to alterations in this connectivity. The flocculonodular lobe is especially implicated in MDD. The lobe is associated with vestibular regulation;  Soza and Aviles (2007)&amp;lt;ref name=”PMID17074443”&amp;gt;&amp;lt;pubmed&amp;gt;17074443&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; found that patients who experienced vestibular vertigo also experienced depressive symptoms. This study also determined that patients who experienced depression also experienced bouts of dizziness. Thus, an unprecedentedly widespread area of the cerebellum is displayed to be connected with emotional memory, in particular, with positive or negative memory retention and could lead towards a cure for depression. &lt;br /&gt;
&lt;br /&gt;
==Dystonia==&lt;br /&gt;
This investigation into a potential link between dystonia -a disorder where muscles contract involuntarily- and the cerebellum attempts to delineate its pathophysiological role in the disease&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;5429509&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The main concern is that the etiology of dystonia appears to be extremely varied, and as such, unpredictable. There is no significant neural degeneration, but in secondary cases there may be structural lesions present in tissue which could be areas of pathophysiology in dystonia. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;27173653&amp;lt;/pubmed&amp;gt;&amp;lt;ref&amp;gt;. Dystonia may manifest itself in almost any body part, indicating that the neural area responsible most likely must not be very specific. This in combination with the involuntary nature of dystonia seems to indicate that the cerebellum is the more than likely involved in the disease. &lt;br /&gt;
&lt;br /&gt;
Basal ganglia abnormalities are hinted to be a causative agent in dystonia.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;9679773&amp;lt;/pubmed&amp;gt;&amp;lt;ref&amp;gt;. The gap in the knowledge of the true interactions between basal ganglia and the cerebellum with regards to dystonia have led to a hypothesis; that the difference in basal ganglia malfunctioning versus abnormal interaction between the ganglia and the cerebellum could reflect the heterogenous pathophysiology of dystonia; either primary or secondary. Some experimental evidence currently available implies that cerebellar dysfunction could affect the topographic distribution of the symptoms of dystonia, and therefore further research is warranted to investigate the full depth of basal ganglia involvement in the disease. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Adaptation to Delayed Action Effects==&lt;br /&gt;
Sensory attenuation refers to when individuals filters unnecessary information. When there is a perturbation between actions and the following-sound, the sensory attenuation is reduced &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
An example of this is when there is a delay when an individual presses a button with sound immediately expected, but instead the sound is delayed. Sensory attenuation can be further described by the forward model theory. The forward model theory suggests that predictions for sensory consequences (for example, sound that is heard) are made simultaneously with the motor movement&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Predictions and real sensory input (what really happens), after the sound delay is conducted, are compared in the model. If the prediction and real sensory input do not matchup, sensory attenuation is observed. The prediction errors are then relayed to other brain areas for further processing&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
The process of sensory attenuation usually re-emerges after the disruption to the normal mechanism &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The re-emerging of this is a process of either correcting previous predictions or updating initial forward models to minimise prediction errors. The cerebellum is currently being researched on how it plays an important role in updating the forward model within the brain&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. One investigation seeks to find evidence on the involvement of the cerebellum in learning to predict the unexpected delays. This investigation has found that low-frequency activity in the cerebellum, prior to the stimulation, plays a key role in adapting to the delayed stimulus &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
==Addiction==&lt;br /&gt;
http://www.sciencedirect.com/science/article/pii/S0149763415002754?via%3Dihub &lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Although there are numerous articles and ongoing research on the cerebellum, there are still investigations yet to be performed. Some questions that could be answered in future research include:&lt;br /&gt;
*Is the cerebellum size related to human intelligence?&lt;br /&gt;
*Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
*What changes in cerebellum development lead to the social impairments seen in those with Autism Spectrum Disorder?&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;28150911&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
*'''Perturbation''' –  (In the context of the Current Research) alternation to the normal mechanism that would happen in response to a stimulation &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=315896</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=315896"/>
		<updated>2017-10-25T12:51:50Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence key historical discoveries, current research and animal models will be discussed. Towards the end of the page there are future questions listed on future investigations involving the cerebellum and the abnormalities from an affected cerebellum are also highlighted. Terms that may be difficult to understand have also been identified and defined.&lt;br /&gt;
&lt;br /&gt;
The following video provides a brief overview on the cerebellum which will be further discussed on the page:&lt;br /&gt;
&amp;lt;html5media height=&amp;quot;315&amp;quot; width=&amp;quot;560&amp;quot;&amp;gt;https://www.youtube.com/watch?v=Fir-v6EoZNE&amp;lt;/html5media&amp;gt; &amp;lt;ref&amp;gt; 2-Minute Neuroscience on Cerebellum. (2015). Retrieved October 25, 2017, from https://www.youtube.com/watch?v=Fir-v6EoZNE &amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;File:CerebellumDiv.png. (2016, December 15). Wikimedia Commons, the free media repository. Retrieved 12:48, October 24, 2017 from https://commons.wikimedia.org/w/index.php?title=File:CerebellumDiv.png&amp;amp;oldid=226277429.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;400&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;1100&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 5:''' (Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 6:''' (Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Developmental Weeks=&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
|&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
|width=&amp;quot;200&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
|  [[File:Stage9 dorsal.jpg|200px|thumb|'''Figure 7:''' Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|'''Figure 8: '''Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb|'''Figure 9:''' Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|'''Figure 10:''' Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|'''Figure 11:''' Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|'''Figure 12:''' Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
[[File:Second Trimester Cerebellum.jpeg|200px|thumb|'''Figure 13:''' Inferior image of a fetal cerebellum at second trimester]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development==&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|'''Figure 14:''' Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum. There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 15:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 16:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers; layers are shown in Figure 15. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 17:''' Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 18:''' SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===Proliferation in the EGL===&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP). &lt;br /&gt;
===Exit from the EGL===&lt;br /&gt;
BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|300px|thumb|'''Figure 19:''' Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;Zhang, G., Assadi, A. H., McNeil, R. S., Beffert, U., Wynshaw-Boris, A., Herz, J., . . . D'Arcangelo, G. (2007). The Pafah1b Complex Interacts with the Reelin Receptor VLDLR. PLoS ONE, 2(2), 252nd ser. doi:https://doi.org/10.1371/journal.pone.0000252&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===FGF and the Isthmus===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
===Reelin and purkinje cells===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
===Transcription factors===&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
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&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Year'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;500&amp;quot; |&amp;lt;center&amp;gt;'''Discoverer''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;700&amp;quot; |&amp;lt;center&amp;gt;'''Description '''&amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1500s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Galen, Vesalius and Varolio&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Described the macroscopic anatomy of the cerebellum&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Late 1700s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Luigi Rolando, Pierre Flourens&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Provided experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Ernesto Lugaro&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | First defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Early 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Joseph Babinski and Gordon Holmes&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Mid 1800s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt; Ramon y Cajal&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | [[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|220px|thumb|right|'''Figure 20:''' Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] &lt;br /&gt;
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Refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed. &lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1880s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;Olof Larsell&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''1960s'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | &amp;lt;center&amp;gt;John Eccles and Janos Szentágothai&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Pieced together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
|}&lt;br /&gt;
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=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
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==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 21:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
[[File:Zebrafish.jpg|210px|thumb|right|'''Figure 22:''' Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
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=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;220&amp;quot;| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|220px|thumb|center|'''Figure 23:''' Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|220px|thumb|center|'''Figure 24:''' Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|220px|thumb|center|'''Figure 25:''' Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|220px|thumb|center|'''Figure 26:''' Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Current Research= &lt;br /&gt;
==Emotional memory in depression==&lt;br /&gt;
Past investigations have concluded that damage to the posterior lobule of the cerebellum can cause individuals to show changes in manner or emotional instability, similar to a degree of depression or psychosis, without an outward cerebellar motor syndrome&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;16434422&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is highly suggestive of the cerebellum's role in emotional memory despite its involvement with motor control. Patients with Major Depressive Disorder (MDD) display a tendency to only selectively recall aspects of scenarios that match their moods, conforming with the &amp;quot;mood-congruent memory (MCM)&amp;quot; theory &amp;lt;ref&amp;gt;Gilligan S. G., &amp;amp; Bower G. H. (1983). Reminding and mood‐congruent memory. Bulletin of the Psychonomic Society, 21, 431–434)&amp;lt;/ref&amp;gt;. This study was undertaken with that principle in mind, and investigated the depth of cerebellar involvement in emotional memory in depression. A link between the volume and density of cerebellar gray matter with measurements of emotional memory was hypothesised. &lt;br /&gt;
&lt;br /&gt;
The experiment was conducted between patients with Major Depressive Disorder (MDD) and healthy controls (HCs)&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;5516611&amp;lt;/pubmed&amp;gt;&amp;lt;ref&amp;gt;. Patients with MDD displayed an atrophy in both gray matter and white matter, most severely in the posterior lobule. There was a significant impairment in emotional memory and decreased volume of the cerebellum in both anterior and posterior lobules. There was marked abnormalities in cortical density, but only a reduction in volume was found to be associated with decreased emotional memory. The severity of depressive symptoms correlated with both volume and density reduction in the grey matter. &lt;br /&gt;
The posterior, anterior and flocculonodular lobes of patients with MDD displayed marked structural differences from the healthy controls, and a functional connectivity between lobules VI and VII of the cerebellum and the cerebrum could indicate that the decreased density in the lobules of MDD patients contributes to alterations in this connectivity. The flocculonodular lobe is especially implicated in MDD. The lobe is associated with vestibular regulation;  Soza and Aviles (2007) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;17074443&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; found that patients who experienced vestibular vertigo also experienced depressive symptoms. This study also determined that patients who experienced depression also experienced bouts of dizziness. Thus, an unprecedentedly widespread area of the cerebellum is displayed to be connected with emotional memory, in particular, with positive or negative memory retention and could lead towards a cure for depression. &lt;br /&gt;
==Dystonia==&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5429509/&lt;br /&gt;
&lt;br /&gt;
==Adaptation to Delayed Action Effects==&lt;br /&gt;
Sensory attenuation refers to when individuals filters unnecessary information. When there is a perturbation between actions and the following-sound, the sensory attenuation is reduced &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
An example of this is when there is a delay when an individual presses a button with sound immediately expected, but instead the sound is delayed. Sensory attenuation can be further described by the forward model theory. The forward model theory suggests that predictions for sensory consequences (for example, sound that is heard) are made simultaneously with the motor movement&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Predictions and real sensory input (what really happens), after the sound delay is conducted, are compared in the model. If the prediction and real sensory input do not matchup, sensory attenuation is observed. The prediction errors are then relayed to other brain areas for further processing&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
The process of sensory attenuation usually re-emerges after the disruption to the normal mechanism &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The re-emerging of this is a process of either correcting previous predictions or updating initial forward models to minimise prediction errors. The cerebellum is currently being researched on how it plays an important role in updating the forward model within the brain&amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. . One investigation seeks to find evidence on the involvement of the cerebellum in learning to predict the unexpected delays. This investigation has found that low-frequency activity in the cerebellum, prior to the stimulation, plays a key role in adapting to the delayed stimulus &amp;lt;ref name=”PMIDPMC5571438”&amp;gt;&amp;lt;pubmed&amp;gt;PMC5571438&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
==Addiction==&lt;br /&gt;
http://www.sciencedirect.com/science/article/pii/S0149763415002754?via%3Dihub &lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Although there are numerous articles and ongoing research on the cerebellum, there are still investigations yet to be performed. Some questions that could be answered in future research include:&lt;br /&gt;
*Is the cerebellum size related to human intelligence?&lt;br /&gt;
*Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
*What changes in cerebellum development lead to the social impairments seen in those with Autism Spectrum Disorder?&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;28150911&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
*'''Perturbation''' –  alternation to the normal mechanism that would happen in response to a stimulation &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=315302</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=315302"/>
		<updated>2017-10-25T05:50:09Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;File:CerebellumDiv.png. (2016, December 15). Wikimedia Commons, the free media repository. Retrieved 12:48, October 24, 2017 from https://commons.wikimedia.org/w/index.php?title=File:CerebellumDiv.png&amp;amp;oldid=226277429.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Fastigial Nucleus'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Interposed Nuclei'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Dentate Nucleus'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Vestibular Nuclei'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain.png|500px]]&lt;br /&gt;
&lt;br /&gt;
(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Developmental Weeks=&lt;br /&gt;
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===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
[[File:Second Trimester Cerebellum.jpeg|200px|thumb| Inferior image of a fetal cerebellum at second trimester]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development==&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum. There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 5:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 6:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, layers show in Figure 5. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 7''': Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 8''': SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===Proliferation in the EGL===&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP). &lt;br /&gt;
===Exit from the EGL===&lt;br /&gt;
BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|300px|thumb|'''Figure 9''': Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;Zhang, G., Assadi, A. H., McNeil, R. S., Beffert, U., Wynshaw-Boris, A., Herz, J., . . . D'Arcangelo, G. (2007). The Pafah1b Complex Interacts with the Reelin Receptor VLDLR. PLoS ONE, 2(2), 252nd ser. doi:https://doi.org/10.1371/journal.pone.0000252&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
===FGF and the Isthmus===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
===Reelin and purkinje cells===&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
===Transcription factors===&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Year'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;500&amp;quot; |&amp;lt;center&amp;gt;'''Discoverer''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;700&amp;quot; |&amp;lt;center&amp;gt;'''Description '''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Early 1500s'''&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | Galen, Vesalius and Varolio&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Described the macroscopic anatomy of the cerebellum&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Late 1700s'''&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | Luigi Rolando, Pierre Flourens&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Provided experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Early 1800s'''&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | Ernesto Lugaro&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | First defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Early 1800s'''&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | Joseph Babinski and Gordon Holmes&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Mid 1800s'''&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | Ramon y Cajal&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''1880s'''&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | Olof Larsell&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''1960s'''&lt;br /&gt;
| width=&amp;quot;40&amp;quot; | John Eccles and Janos Szentágothai&lt;br /&gt;
| width=&amp;quot;80&amp;quot; | Pieced together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|200px|thumb|Figure 10:  Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 11:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
[[File:Zebrafish.jpg|210px|thumb|right|Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|250px|thumb|Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|250px|thumb|Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|250px|thumb|Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|250px|thumb|Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Current Research= &lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5516611/&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5429509/&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571438/&lt;br /&gt;
&lt;br /&gt;
http://www.sciencedirect.com/science/article/pii/S0149763415002754?via%3Dihub &lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Is the cerebellum size related to human intelligence?&lt;br /&gt;
&lt;br /&gt;
Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=314660</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=314660"/>
		<updated>2017-10-24T05:47:35Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Fastigial Nucleus'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Interposed Nuclei'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Dentate Nucleus'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Vestibular Nuclei'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
&lt;br /&gt;
(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Developmental Weeks=&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Neural Development==&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 5:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 6:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, layers show in Figure 5. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 7''': Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 8''': SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP).  BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|350px|thumb|'''Figure 9''': Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;1800349&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
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&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|200px|thumb|Figure 10:  Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
&lt;br /&gt;
Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 11:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. [[File:Zebrafish.jpg|210px|thumb|right|Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|250px|thumb|Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|250px|thumb|Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|250px|thumb|Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|250px|thumb|Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Current Research= &lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5516611/&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5429509/&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571438/&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Future Questions=&lt;br /&gt;
Is the cerebellum size related to human intelligence?&lt;br /&gt;
&lt;br /&gt;
Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=314658</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=314658"/>
		<updated>2017-10-24T05:45:31Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
='''Cerebellum'''=&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;&amp;gt;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref name=&amp;quot;Venturini, S. (2017, October 21). The Cerebellum. Retrieved October 23, 2017, from http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;quot;/&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;The Blood Supply of the Brain and Spinal Cord. (2001). In D. Purves, G. Augustine, &amp;amp; D. Fitzpatrick (Eds.), Neuroscience (2nd ed.). Sunderland, MA: Sinauer Associates.&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 1.43.55 pm.png|thumb|'''Figure 4:''' (A). Cell types and where they are found in the cerebellar cortical layers. (B) Shows how the different layers of the cerebellum can be easily determined. P - the Purkinje layer; G - the granular layer; M - the molecular layer; W - the white matter. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3527225&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; ]]&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;Danbolt, N. C., &amp;amp; Zhou, Y. (n.d.). The Cerebellar Cortex. Retrieved October 23, 2017, from http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;D’Angelo, E. (2013). Cerebellar Granule Cell. Handbook of the Cerebellum and Cerebellar Disorders, 3, 767-791. doi: 10.1007/978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;Harting, J. K. (1997). Deep Nuclei. Retrieved October 23, 2017, from http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Fastigial Nucleus'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Interposed Nuclei'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Dentate Nucleus'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |'''Vestibular Nuclei'''&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;12418089&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
&lt;br /&gt;
(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;22237006&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19335795&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Developmental Weeks=&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref name=&amp;quot;PMID21380713&amp;quot;/&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Neural Development==&lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 5:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 6:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Overview of Development===&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles:&lt;br /&gt;
*Prosencephalon&lt;br /&gt;
*Mesencephalon &lt;br /&gt;
*Rhombencephalon&lt;br /&gt;
The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The cerebellar territory is defined by the expression of Hoxa2 genes (from posterior) and Otx2 (from anterior) genes and these genes are controlled by proteins Wnt and fibroblast growth factor families which regulate the expression of these genes in order to establish the cerebellar territory &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when the primary fissure deepens by the end of the third month and thus divides the vermis, shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
===Overview of Cerebellar Cell Development===&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, layers show in Figure 5. &lt;br /&gt;
*Molecular Layer: consists of excitatory granular cell axons, purkinje cell dendritic fibres. stellate and basket cells.&lt;br /&gt;
*Purkinje Cell Layer: consists of a single layer of inhibitory Purkinje cells. &lt;br /&gt;
*Granular Cell Layer: Dense layer of excitatory granule cells, golgi cells and unipolar brush cells.&lt;br /&gt;
&lt;br /&gt;
The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. The dorsomedial ventricular zone of the fourth ventricle gives rise to the principal neuronal output, the Purkinje cell and other neurons within the cerebellum The secondary germinal zone, coming from the adjacent rhombic lip generates the cerebellar granule cells as well as a subpopulation of neurons of cerebellar nuclei and several precerebellar nuclei &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;.&lt;br /&gt;
Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cell &amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref name=&amp;quot;PMID4552263&amp;quot;/&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions.&amp;lt;ref name=&amp;quot;PMID3213765&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the [https://en.wikipedia.org/wiki/Rhombic_lip rhombic lip]  to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the [https://en.wikipedia.org/wiki/Pia_mater pia mater] and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;16806506&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;Sotelo, C., &amp;amp; Rossi, F. (2013). Purkinje Cell Migration and Differentiation. Handbook of the Cerebellum and Cerebellar Disorders, 2, 147-178. doi:10.1007/978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png|500px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 7''': Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cell Signalling in Cerebellar Development==&lt;br /&gt;
[[File:Cell signalling in cerebellum development.jpg|500px|thumb|'''Figure 8''': SHH (green) acts on EGL to stimulate proliferation, on Bergmann glia (B) to induce differentiation, and has an unknown function on purkinje cells (P).  Laminin and heparan sulfate have a synergistic effect on SHH and fibronectin and vitronectin have an inhibitory effect on SHH.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;22291620&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Many different cell signalling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  [https://en.wikipedia.org/wiki/Sonic_hedgehog '''Sonic hedgehog'''] (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The '''external germinal layer''' (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for '''Atoh1''', a transcription factor that represses differentiation and promotes division via SHH signalling.  In a similar manner to SHH and Atoh1, the pia mater secretes '''Sdf1''' which interacts with the receptor '''Cxcr4''' to maintain proliferation in the EGL. [https://en.wikipedia.org/wiki/Notch_signaling_pathway Notch2 signalling] and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP).  BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of '''Neurod1''' and interaction with the extracellular matrix components of the inner EGL, '''vitronectin''', '''F3''', and '''contactin'''.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;  Granule cell migration is stimulated by '''D-serine''' secreted by the Bergmann glia.  This can be inhibited by '''DAAO''' or '''SR'''.&amp;lt;ref name=&amp;quot;PMID16806506&amp;quot;/&amp;gt; &lt;br /&gt;
&lt;br /&gt;
[[File:Reelin signalling.jpg|350px|thumb|'''Figure 9''': Reelin is a large signalling molecule that initiates a signal transduction pathway to induce formation of a monolayer of purkinje cells and detach purkinje cells from radial glia.&amp;lt;ref&amp;gt;&amp;lt;Pubmed&amp;gt;1800349&amp;lt;/Pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
[https://en.wikipedia.org/wiki/Fibroblast_growth_factor '''Fibroblast Growth Factor'''] (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of [https://en.wikipedia.org/wiki/Rhombomere rhombomere] 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[https://en.wikipedia.org/wiki/Reelin '''Reelin'''] is an important signalling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors '''VLDLR''' and '''ApoER2''', adaptor protein '''Dab1''', and many other further downstream intracellular signalling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors [https://en.wikipedia.org/wiki/Hox_gene '''Hoxa2'''] and '''Otx2'''.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref name=&amp;quot;PMID3051031&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
[[File:Screen Shot 2017-10-16 at 3.01.32 pm.png|200px|thumb|Figure 10:  Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum. Drawn by Santiago Ramón y Cajal, 1899. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4308982&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
&lt;br /&gt;
Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref name=&amp;quot;PMID25336734&amp;quot;/&amp;gt;&lt;br /&gt;
&lt;br /&gt;
http://www.nature.com/nprot/journal/v12/n4/full/nprot.2017.001.html&lt;br /&gt;
https://www.nature.com/articles/srep36131&lt;br /&gt;
&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
[[File:Isthmic Organiser.png|thumb|'''Figure 11:''' Isthmic Organiser &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3870571&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
&lt;br /&gt;
==Cell Structures==&lt;br /&gt;
The cellular structures in the cerebellum (including Purkinje cells and granule cells) have been investigated in various animal models. One animal model is the zebra fish which is a bony fish (teleosts). Like mammals, the zebrafish cerebellum contains several types of neurons which function as either excitatory or inhibitory neurons &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. [[File:Zebrafish.jpg|210px|thumb|right|Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. &amp;lt;ref name=”PMIDPMC4584246”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4584246&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]] Glutamate is utilised by excitatory neurons as their major neurotransmitter. Excitatory neurons include granule cells, unipolar brush cells and eurydendroid cells. The eurydendoid cells are predicted to be correspondingto the deep cerebellar neurons in mammals &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The inhibitory neurons use y-aminobutric acid (GABA) and/or glycine (also known as GABAergic neurons) for neurotransmission. Purkinje cells, Golgi and stellate cells are inhibitory neurons. However, a difference between mammal and teleosts is the lack of basket cells. Basket cells are GABAergic neurons that contribute project their axons to the Purkinje cells &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. This is important, because as earlier highlighted Purkinje cells (inhibitory neurons) and granule cells (excitatory cells) contribute to the three cortical layers of the cerebellum. This model is important for understanding what structures contribute to the neurotransmission process in the cerebellum. &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS) which will be explained in the table below.&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Abnormality'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Brain Imaging'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Dandy-Walker Malformation'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The causes of DWM are still being researched and hence there has not been any clear causes. However, some causes include maternal diabetes, chromosomal defects that affect foetal brain development, infections in the mother that pass to the developing foetus and exposure of the unborn baby to certain toxins.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;&amp;gt;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;lt;/ref&amp;gt; Symptoms of DWM include motor and speaking development delays, poor muscle coordination, vision and hearing impairment.&amp;lt;ref name=&amp;quot;Pediatric Dandy-Walker Malformation. (2017). Retrieved October 23, 2017, from https://childrensnational.org/choose-childrens/conditions-and-treatments/fetal-carepregnancy/dandy-walker-malformation&amp;quot;/&amp;gt; &lt;br /&gt;
| [[File:DandyWalkerMalformation.jpeg|250px|thumb|Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| &amp;lt;center&amp;gt;'''Joubert Syndrome'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development. JS is inherited as mutations in any of many genes, however, how mutations lead to JS is still being investigated. Mutations cause problems in the structure and function of cilia and hence signalling pathways may be disrupted during development &amp;lt;ref&amp;gt; Joubert syndrome. (2016). Retrieved October 22, 2017, from https://rarediseases.info.nih.gov/diseases/6802/joubert-syndrome&amp;lt;/ref&amp;gt;.&lt;br /&gt;
| [[File:JoubertSyndrome.jpg|250px|thumb|Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| &amp;lt;center&amp;gt;''' Chiari Syndrome I-III'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. As a result of genetic mutations or maternal diet lacking vitamins or nutrients, structural defects in the brain and spinal cord can occur during foetal development leading to Chiari Syndrome &amp;lt;ref&amp;gt; Chiari Malformation Fact Sheet. (2017). Retrieved October 22, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet&amp;lt;/ref&amp;gt;&lt;br /&gt;
| [[File:ChiariMalformation.jpg|250px|thumb|Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot;&lt;br /&gt;
| &amp;lt;center&amp;gt;'''Rhombencephalosynapsis'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Rhombencephalosynapsis is predicted to result from disturbed cerebellar development at approximately 33–34 days of gestation &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cause of rhombencephalosynapsis is thought to be a genetic defect in the isthmic organizer, resulting in abnormal dorsal patterning, causing the mentioned defects &amp;lt;ref name=”PMID18409180”&amp;gt;&amp;lt;pubmed&amp;gt;18409180&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum. Rhombencephalosynapsis can be identified from a range of symptoms, from involuntary muscle coordination, severe cerebral palsy or mental retardation&amp;lt;ref name=”PMID25816977”&amp;gt;&amp;lt;pubmed&amp;gt;25816977&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
| &amp;lt;center&amp;gt;[[File:Rhombencephalosynapsis.jpg|250px|thumb|Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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=Current Research= &lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5516611/&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5429509/&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571438/&lt;br /&gt;
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=Future Questions=&lt;br /&gt;
Is the cerebellum size related to human intelligence?&lt;br /&gt;
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Does the p53 gene function in cerebellum development? If so, does this function relate to the development of embryonic cancers? &amp;lt;ref name=”PMC4853753”&amp;gt;&amp;lt;pubmed&amp;gt; 4853753&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Terms=&lt;br /&gt;
&lt;br /&gt;
* '''Basket cells'''– multipolar GABAergic interneurons. They are located on different regions of the brain and cerebellum. They function in making inhibitory synapses and control the overall potential of target cells. &lt;br /&gt;
* '''Bergmann Glia ''' – they are a type of radial astrocyte, cell bodies are in the Purkinje cell layer of the cerebellum. &lt;br /&gt;
* '''Cerebellar nuclei ''' – These cells receive inhibitory inputs from the purkinje cells, and excitatory inputs from mossy and climbing fibres. &lt;br /&gt;
* '''Climbing fibres ''' – provide excitatory input to the cerebellum, they have a crucial role in motor behaviors. Axons pass through the pons, then synapse with the deep cerebellar nuclei and purkinje cells. &lt;br /&gt;
* '''Deep nuclei cells''' – Purkinje cells project to the deep nuclei cells and these are the only form of output cell in the cerebellar cortex. They also receive excitatory inputs from the mossy and climbing fibers. &lt;br /&gt;
* '''Dendrites ''' – an extension of a nerve cell, impulses travel along these extensions and they synapse at another cell body. &lt;br /&gt;
* '''Flocculonodular lobe ''' – lobe of the cerebellum that consists of a nodule and the flocculus. It is located on the anteroinferior surface of the cerebellum.&lt;br /&gt;
* '''Glia cells ''' – They are nonneuronal cells and they support cells and they surround neurons and insulate them, there are many types of glia cells: oligodendrocytes, ependymal cells, astrocytes, Schwann cells etc. &lt;br /&gt;
* '''Granule cells ''' – are small neurons, and they are the most numerous in the brain. They are packed in a thick layer of the cerebellar cortex and emit only 4 or 5 dendrites. They receive all input from mossy fibres. &lt;br /&gt;
* '''Mossy fibres ''' – major input of the cerebellum, relays sensory information from the pons to the granule cells and then sent to the purkinje cells for processing. &lt;br /&gt;
* '''Neural tube ''' – a hollow prenatal structure that forms the brain and spinal cord. Formed by the folding and fusion of the opposite ectodermal folds. &lt;br /&gt;
* '''Pons ''' – a part of the brain that links the medulla oblongata and the thalamus.&lt;br /&gt;
* '''Purkinje cells ''' – a class of GABAnergic neurons that are located in the cortex of the cerebellum, they are large, branched cells. &lt;br /&gt;
* '''Stellate cells ''' – in the cerebellum, they are located in the molecular layer and they synapse onto purkinje cells. &lt;br /&gt;
* '''Vermis ''' – rounded and elongated section of the central part of cerebellum, lies between the two hemispheres. &lt;br /&gt;
* '''Vetrobrobasilar System ''' – consists of the two vertebral arteries and one basilar artery and these are located towards the back of the brain. Provide around 20% of the intracranial bloody supply. &lt;br /&gt;
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{{Glossary}}&lt;br /&gt;
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=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_5&amp;diff=311324</id>
		<title>Talk:2017 Group Project 5</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_5&amp;diff=311324"/>
		<updated>2017-10-12T02:34:48Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Review */&lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
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==Suggested Starting Places==&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 5 below are some starting places.&lt;br /&gt;
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{{Respiratory Links}}&lt;br /&gt;
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PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Lung+Development ''Lung Development''] | [http://www.ncbi.nlm.nih.gov/pubmed?term=Respiratory+Development ''Respiratory Development'']&lt;br /&gt;
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BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Lung+Development ''Lung Development'']&lt;br /&gt;
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Recent papers&lt;br /&gt;
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&amp;lt;pubmed limit=5&amp;gt;Lung+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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=Peer Review=&lt;br /&gt;
This paper is divided into logical categories and has very good layout. The student drawings are all good, and the developmental timeline is very informative. Most images are well-referenced and have the appropriate Copyright, except the images in the 'Developmental signaling processes' section which lack a description and Copyright. The &amp;quot;Structure of Respiratory Network&amp;quot;, &amp;quot;Developmental signalling processes&amp;quot;, &amp;quot;Research&amp;quot; and &amp;quot;Animal models&amp;quot; sections of the page lack in-text citations and thus lack credibility. &lt;br /&gt;
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The use of movies is very clever and helpful provided using content off the UNSW Embryology Wiki page is permitted. The layout of the entire page is very good, however the size of some of the images needs to change as they appear pixillated and blurry. Images could include a small description directly under them to direct the reader to what they are looking at. The references need to be fine tuned, and some grammatical errors need to be addressed. This page would benefit from a lengthier introduction leading in to lung development and a glossary list. Otherwise this is a very informative page!&lt;br /&gt;
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Future questions and current research subheadings are incomplete. Don’t forget to add references, copyright statements and the student image template to each of the images that have been used on the wikipage. References should be used on Lung Histology to show the research that has been done. The animal models section is comprehensive but there are barely any references to show where the information was found. &lt;br /&gt;
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Subheadings and content that have been used show a good understanding of the topic area. The team have used their own images to show their understanding. The team has used images in the ‘Developmental timeline’ table which shows comprehensive research. The images have brief descriptions below them, hence readers will be able to understand what the image is displaying. Important words in relation to the lung have been bolded. The abnormal development section is done comprehensively with references and images. References were cited properly, however there is an error on reference 20. &lt;br /&gt;
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The project page is looking good. I particularly found the developmental timeline to be very informative and easy to follow. I like the fact that you have used a table here to display it along with diagrams that fit each stage, with each diagram being cited and referenced correctly. &lt;br /&gt;
I think the diagram that is related to the histology section could be a little clearer to read as it is a little jumbled and slightly hard to distinguish everything.  &lt;br /&gt;
The section on developmental signaling processes is good, and gives the detail without making the section too long and complicated. &lt;br /&gt;
‘current understandings and areas of research’ has no information as of yet, it would be good to add some recent research papers with a short summary.&lt;br /&gt;
The use of movies is helpful, but maybe consider moving them further up the page, to a more relevant section, the beginning of ‘developmental origin’ would be better. &lt;br /&gt;
A glossary of terms would be helpful, as some of the jargon is complicated. &lt;br /&gt;
There seems to be a citing error in the reference list that should be dealt with. &lt;br /&gt;
Overall it is a very interesting topic and I think you have executed it well so far&lt;br /&gt;
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The page is quite informative, however there are incomplete sections including the introduction and the last few topics towards the end. There is a clever use of self drawn images to avoid any copyright issues, but the lung histology image can be a bit hard to read due to the lack of contrast (the grey outline and font being a bit light to read) and the image itself is bit unclear (Is it a lateral view? cross sectional? towards the apex of the lung?). The bolding of main terms at the start of the page is a nice touch, it would work better if there was a glossary at the end of the page stating the bolded terms and their meaning. It would also be better if the rest of the page had their main terms bolded as well and added to the glossary. The movies section seemed a bit out of place and did not flow from the previous and next topics, it would be better to move them into the &amp;quot;developmental&amp;quot; topics. In the abnormal development and animal models sections, more images that correlate to each subheading would be advised to help the reader visualise the abnormalities or results instead of reading chunks of words. Such images could include x-rays, images of physical observations of sufferers, graphs and figures. Development of the lungs topics were easy to: follow, read and understand, which is extremely important. Ref 22 isn't stated properly.&lt;br /&gt;
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The project has a very good lay-out and is written relatively clearly. The table with the developmental timeline and historical discoveries of those developmental stages is excellent and the images that go along with each stage are relevant and have a summary and the appropriate copyright information when you click on them. Some pictures on the page do not have the appropriate copyright information or a summary of them when clicking on them that still needs to be added. In-text citations need to be added to a lot of the sections. There are 7 in-text citations at the beginning of the references section that do not refer to any specific information that should be moved to the appropriate information. &lt;br /&gt;
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The information in the project is good and you explain studies that have been done to determine this information throughout the project which is an effective way to describe past and current research. There is currently no information under “Current understandings and areas of research” and “Future questions,” but these headings could potentially just be eliminated. &lt;br /&gt;
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The project is relatively clear but a couple things could be added, changed, or moved to add more clarity. There are some basic grammatical issues and spelling errors that can easily be fixed (e.g. “These branching structures involve are regulated by a network of signalling factors”). In “Developmental signalling processes,” adding whether each signalling molecule is either a ligand, receptor, or transcription factor (e.g. Sox9 is a transcription factor, SHH is a ligand, and HS-GAG is a receptor), what cells these molecules are expressed in, and which cells these molecules act on (if different than where they’re expressed) may make this section clearer. In “Animal Models” the introduction of mouse models would make more sense if there was an explanation of the mice used in the studies (i.e. what strains of mice are used, how are they genetically modified, do these mutations result in a KO, etc.) rather than just the genes being looked at. &lt;br /&gt;
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Overall good project. Referencing needs to be fixed, summary and copyright information needs to be added to some pictures, and blank subheadings either need information or should be eliminated. The information in the project is good, the lay-out is good, the interspersed information about research is good, and the pictures support the information well. &lt;br /&gt;
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This page is very informative, the headings and subheadings were highly appropriate and made the development process much easier to follow. There is a relevant amount of background information under &amp;quot;Lung Anatomy, Histology and Vasculature&amp;quot;. Although most sections were cited correctly, some areas were missing references, such as &amp;quot;Structure of Respiratory Network&amp;quot;, and &amp;quot;Lung Anatomy and Histology&amp;quot; . A good amount of images were used (images were very well drawn and easy to understand) and they were accompanied with relevant information. Perhaps you could add in more images in the Abnormal development section? I enjoyed reading the table of &amp;quot;Developmental Timeline&amp;quot; as it was very easy to understand and had appropriate images. Future questions and Glossary were left blank and would be very useful if they were done but I assume that they would be completed with time. Overall, the page seems to have a good amount of information on it so far, well done.&lt;br /&gt;
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This wiki page is very informative and a good read! When reading I noticed that the images don’t have a figure number, although this isn’t necessary, it can make it easy to refer to figures in text and therefore explain them better. For the heading lung histology, you can add proper dot points by adding an asterix before the information, this will make your page present better. Both headings future questions and current research need to be finished as they are incomplete. Using self drawn pictures makes your page easy to follow and understand, this is a great feature of your page. Copyright information is added well for the most part, however I found some images under the heading “Developmental signaling processes” which didn’t have any copyright information or an appropriate description, also make sure the student template is added at the end of every image description. I particularly enjoyed the timeline, it is very well written and is easy to understand. Good job on the project thus far.&lt;br /&gt;
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A good page going through a lot of the main steps required for the project page, but the page needs a lot of references. &lt;br /&gt;
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* '''The Lung Anatomy, Histology, and Cardiovasculature''' sections give a good and short understanding of the lungs. The Histology part could need a better layout using the wiki-formatting. All the sections need references! There are almost no references in these sections. I like the big introduction to the lungs, but I am not sure how much it has to do with the embryonic development – especially the Histology part. The self-drawn pictures support the learning when reading, but they are a bit weak in colors. I must click on the figure and then zoom to read and see details of the figures. It would be nice if you can see details at the same time reading the project page. Maybe you should draw the pictures with a more colorful pen. &lt;br /&gt;
*'''The developmental timeline''' is really detailed and has a lot of pictures to support the understanding. The images have the right information.&lt;br /&gt;
*'''The Conducting System''' section has two pictures that need more information on the picture page – like copyright information. You can look on the image tutorial how do give a picture page proper information or look through some of the other sections on your group project.&lt;br /&gt;
*'''Alveolus: the functional unit:''' This section explains a study about overweight in pregnancy, but does not give the reference of the study. It is important to tell the reader where you found this study. &lt;br /&gt;
*'''Developmental signaling processes''' section gives a good, short description. Easy to read and understand. But both pictures are missing detailed information – also copyright information. You also mention “a recent study” without giving a reference to the study. &lt;br /&gt;
*'''Current understandings and areas of research''' section is missing the context.&lt;br /&gt;
*'''Animal Models''' section has a good context and a good setup but could use a brief introduction to what you are going to talk about. Maybe also a figure could be nice to support the reading. You also mention Bmp as a key pathway but does not explain much about it. Since it is mentioned in the short introduction, then the reader would expect that there will be more information about that specific pathway. &lt;br /&gt;
*'''Abnormal Development''' is a really good section. It has a lot of references, is easy to read and understand, has the right information on the pictures, beautiful layout. I like that it gives a short understanding of the different abnormalities.&lt;br /&gt;
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This page is really impressive when the hand drawn images caught my eye as well as the balanced text-to-images ratio. It is well organised and there was a decent flow throughout the page. It is useful that keywords were formatted to be in bold formatting to draw the attention of the readers to the main terms. The development timeline is very fascinating, it had a description as well as images. Summaries are well-informative as well as brief in some sections. Some images were reference properly and copyright approval was provided. Abnormal development was neatly organised into sections and appropriate journal articles for evidence. However, there are a few abnormalities that did not feature an image to provide more visual aid to the readers. &lt;br /&gt;
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The 'Alveolus' was left in bold format while the rest were in normal format, this could be easily changed in the edit page. The hand drawn images did not provide a reference where it was based off. Also, one of the images has a very low resolution (&amp;quot;This image is a stylised typical developmental branching pattern over time in a lung bud.&amp;quot;). The images should be encased in boxes and a label underneath would be neater. Laboratory results from the animal models would be useful to see. The lung histology section didn't provide any references. The movies section disrupts the flow of the sections, it might be best to place them at the bottom of the page.&lt;br /&gt;
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This page seems like it is almost complete.&lt;br /&gt;
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Revise the reference list. Some were left as links and the overall reference formatting was inconsistent. Some were left as APA format and some were left in another format. There was a cite error in one of the references as well.&lt;br /&gt;
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Overall, this page has a good arrangement of information. For the lung anatomy, histology and cardiovasculature, the content is concise and good. The images were all self drawn and a lot of effort has been put to it. Good job to the person who did it. However, for the lung anatomy, histology and cardiovasculature, there are no references at all. Also, for the lung histology, perhaps adding in histological images and referencing it when writing the text would make the section better. The developmental timeline was also very well done. I love how all the information was presented in a table and was easy to follow through. The images had their copyright statements, brief overview and proper referencing. Again, there are no references for the structure of respiratory network and its sub sections and for the developmental signalling sections. Also, the images should be labelled as figure 1 or table 1 and could be mentioned in the text where appropriate. Perhaps a glossary could benefit this page. The abnormalities section was well referenced and there was a fair amount of abnormalities covered. Maybe more images could be added.&lt;br /&gt;
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This page is very well-structured and demonstrates an extensive understanding of the topic at hand. I found the headings and subheadings easy to follow and contributes to a smooth flow of the page which had a very ‘step-by-step’ feel. References are fairly consistent throughout, however a significant amount of the areas are lacking any acknowledgement to research including the information under the subheading “Animal Models”, “Developmental signaling processes”, etc.  Good use of diagrams, especially in depicting the anatomical and histological features of the lung and linking to key points on the timeline – I felt it accompanied the text really well and did not overcomplicate or confuse the concepts. Referring to these images as figures would enhance the quality of the writing overall. Perhaps a section on the functionality of lung structures or an expansion on the function of the layers would provide a good understanding of the topic – I found a lack of focus towards functional aspects overall (only mentioned briefly under “Lung Anatomy”). Entries into the glossary would have helped with understanding the text. &lt;br /&gt;
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I don't like that first sentence above Lung Anatomy below the Lung heading. I feel like it is just dumped there so maybe try expanding on this a little bit and making it more into an introduction. The information in the lung anatomy is really good, and that drawing is too! The only suggestion I would make here is instead of saying &amp;quot;this diagram&amp;quot;, instead refer to it as Figure 1 and then label the image Figure 1. The lung histology information and picture again was really good, however same thing with reference to the image as I suggested for anatomy. Same thing with cardiovasculature reference to images. The timeline is really great, label your images as figures again though and then can have the little explanation. The brief summary above the timeline could look more structured if you placed it in a simple table.The rest of your information is good, however, some suggestions I would like to make to improve your page would be adding some videos in. These are always engaging and offer a different style of learning for people. A glossary of key terms could also benefit your page. Referencing overall looks good, however, there are a few errors in your referencing. Overall really great page though.&lt;br /&gt;
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This project page is very detailed and extensive yet still clear and easy to follow. The tables and many diagrams make the page very engaging. The material is relevant and informative. The structure is well layed out with the use of headigs and subheadings. The use of movies in the ‘current understandings and areas of research’ is very creative and makes the content easier to understand. You have clearly put a lot of time and effort into this project and I only have a few minor recommendations for improvement. Firstly the in-text referencing is minimal in some sections and this should be worked on before the project is due. Also a more detailed and descriptive introduction section could be used to explain what the project is about. Also some of the diagrams I believe are too large and are overwhelming on the page. A large heading of ‘The Lungs’ could also be placed at the top of the page in larger writing to make it more engaging, perhaps with a simple diagram of the lungs. &lt;br /&gt;
Overall, congratulations this project is extremely well done.&lt;br /&gt;
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Lung histology and cardiovascular  are beautifully drawn but maybe the terms could be bolded because it is a little hard to fully make out the labels on the diagrams.  I like that you guys integrated both the information and diagrams together by referring to them in the text instead of just planting the image there without referring to it.  It makes the page enjoyable to read.  Also, referencing done throughout the abnormalities section is thorough and indicative of the extensive research done on it, good job. For the developmental timeline, it might help to move the pictures below the table--and label the images-- so that the table is only text and more easy to read all in one instead of having the images adding unnecessary spacing.  This may be a personal preference however.  For developmental signalling processes, both images containing information about FGF10 have the descriptions below them.  It might help to add that descriptions to the images themselves so that they don’t interrupt the flow of that section.  There is some information missing from current research, future questions, and glossary hat need to be completed as well.&lt;br /&gt;
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This peer review is based on the relevant dot points of the ‘Group Assessment Criteria’, as well as subheadings suggested by Mark. This information can be found on the student page. &lt;br /&gt;
{| border=&amp;quot;1&amp;quot; align=&amp;quot;left&amp;quot;&lt;br /&gt;
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|Criteria&lt;br /&gt;
|Strengths&lt;br /&gt;
|Weaknesses&lt;br /&gt;
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| 1. The choice of content shows a good understanding of the topic area&lt;br /&gt;
| The developmental timeline is excellent; this section is very detailed and the ideas are expressed clearly. The accompanying images for each stage of development enhance the information in the table and make some of the more complex ideas easier to visualize.&lt;br /&gt;
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The ‘lung anatomy’ and ‘lung histology’ sections provide background information that makes the rest of the wiki page easier to comprehend. The student-drawn images in these sections are really well done, and make the ideas in the text easier to understand.&lt;br /&gt;
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The ‘animal models’ and ‘abnormal development’ sections are explained clearly and in detail.&lt;br /&gt;
The ‘key discoveries’ component of the assignment was addressed well (I liked how it was integrated with the developmental timeline). &lt;br /&gt;
The information in ‘developmental signaling processes’ was expressed clearly, and covered the section in adequate detail. The accompanying images also enhance the information presented in this section. &lt;br /&gt;
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Overall, the wiki page has an excellent layout, with the chosen sub headings making the page easier to follow. &lt;br /&gt;
| The ‘future questions’ and ‘current research’ sections of the wiki page lack content. There are some references to current research throughout the wiki page (see ‘alveolus: the functioning unit), however descriptions of the findings are often vague and there is no information included about the source (e.g. the authors, the date, the title of the research paper).&lt;br /&gt;
&lt;br /&gt;
Some sections of the wiki page may be improved by adding visual aids (e.g. in ‘animal models’) &lt;br /&gt;
|--&lt;br /&gt;
|2. Content is correctly cited and referenced&lt;br /&gt;
|There have been attempts at referencing throughout the assignment. A reference list has been produced and appears mostly correct. The ‘abnormal development’ section was referenced particularly well.&lt;br /&gt;
&lt;br /&gt;
The reference list is extensive, with the majority of the sources being peer-reviewed primary research articles.  &lt;br /&gt;
&lt;br /&gt;
Most of the images on the wiki page have been referenced correctly (see all images in ‘developmental timeline’) &lt;br /&gt;
|Referencing throughout the wiki page is inconsistent. Many areas lack referencing entirely (see ‘lung anatomy’ and ‘lung histology’), and other sections have minimal in-text citations. Remember to cite any information that is not original (in either wording or idea)&lt;br /&gt;
&lt;br /&gt;
Student drawn images from the ‘lung anatomy’, ‘lung histology’ and ‘lung cardio vasculature’ are not referenced correctly. Remember to cite the source from which the image was derived. &lt;br /&gt;
&lt;br /&gt;
Some references have been repeated in the reference list (see references 15 and 16).&lt;br /&gt;
|-&lt;br /&gt;
|3. The wiki has an element of teaching at a peer level&lt;br /&gt;
|The information on the wiki page is written at a level appropriate for peers. The ‘anatomy of the eye’ section provides background information that clarifies information further down the wiki page. &lt;br /&gt;
&lt;br /&gt;
Most of the included diagrams and tables enhance the written information.&lt;br /&gt;
|Many of the acronyms and terms used in this assignment are either poorly explained, or not explained at all. Be sure to add definitions under the ‘glossary’ section so the reader can more easily comprehend some of the more difficult subject areas.&lt;br /&gt;
&lt;br /&gt;
Some images on the page don’t have descriptions. Try adding descriptions to make the images easier to understand. &lt;br /&gt;
|-&lt;br /&gt;
|4. Relates the topic and content of the Wiki entry to learning aims of embryology&lt;br /&gt;
|The wiki page addresses most of the relevant aims of embryology, including embryonic development, abnormal development, signaling processes, animal models and key discoveries.&lt;br /&gt;
|The wiki page lacks content relevant to other aims of embryology, such as current research. Be sure to add some information under this sub-heading. &lt;br /&gt;
|-&lt;br /&gt;
|5. The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic&lt;br /&gt;
|Much of the content on the page has been well researched, particularly the developmental timeline. &lt;br /&gt;
&lt;br /&gt;
The extensive reference list shows that, overall, this topic has been well researched across a wide variety of sources.&lt;br /&gt;
|No links to other pages on the UNSW embryology wiki have been included. Try linking this wiki page to other aspects of the embryology wiki, such as the ‘lecture 11- respiratory’ page. &lt;br /&gt;
|}&lt;br /&gt;
---&amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&amp;lt;b&amp;gt;Strengths:&amp;lt;/b&amp;gt; &amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	The wiki page appears to explore a variety of topics regarding the development of the lung, ranging from topics such as lung anatomy and histology, developmental origin andt and also abnormalities associated with development. Furthermore, all topics are relevant to lung development (criteria 1). In addition, a variety of images, tables and movies have been utilized alongside the written-text (criteria 2). This helps present information to students who prefer to learn visually. &amp;lt;br&amp;gt; &lt;br /&gt;
•	The contents are presented in an appropriate level for the peer. The author for most of the time attempts to provide clarification for acronym accompanied with images and tables that make it easier for the peer learning (criteria 4). &amp;lt;br&amp;gt;&lt;br /&gt;
•	The authors of this wiki page have also successfully described evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities (criteria 5) by exploring animal models that have contributed to our understanding of lung development. The authors have made an excellent start by describing mouse models with respect to different gene signaling processes and their involvement in lung development.&lt;br /&gt;
&amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
&amp;lt;b&amp;gt;Areas of improvement:&amp;lt;/b&amp;gt; &amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	Authors should provide a more detailed description of the signaling processes involved in lung development (FGF and SHH)., Also, very few signaling pathways have been listed under this subheading. &amp;lt;br&amp;gt;&lt;br /&gt;
•	The author seems to have some citation errors in the reference list (article 22). Some section (lung anatomy, lung histology, the conducting system, alveolus and current research) seem to not have any in-text citation. The articles on hyaline membrane disease seem very old and they could be outdated. &amp;lt;br&amp;gt;&lt;br /&gt;
•	Some subheadings are not explained in details (lung cardiovascular) whereas other  (current understanding and area of research and future question) lack contents.&lt;br /&gt;
•	Some acronyms lack clarification such as Sox9 and HS-GAG as the author provide a brief description of their role without attempting to explain what they are. Also, some of the drawn images are not very clear for the reviewer. &amp;lt;br&amp;gt;&lt;br /&gt;
•	Authors may have described the history of research which may have contributed to our current understanding of lung development. For example a timeline may be developed to clearly describe this (criteria 6).&lt;br /&gt;
&lt;br /&gt;
Grade: DISTINCTION&lt;br /&gt;
&lt;br /&gt;
General Comment:&lt;br /&gt;
This wiki page has addressed most aspects of this assignment really well. Only a few areas need some improvement.&lt;br /&gt;
&lt;br /&gt;
--- &lt;br /&gt;
'''Peer review project 5''' &lt;br /&gt;
&lt;br /&gt;
* The project contained both developmental origin, timeline, signalling processes, current research and findings, animals model and abnormal development sections. The project therefore has all the sections which were a requirement for the project. But when you read the developmental origin section it does not say which germ layer it comes from. That is written in another section which I find confusing. &lt;br /&gt;
* Good idea drawing your own pictures, but because it is done with a pencil it is difficult to see what’s written on the picture. &lt;br /&gt;
*  I like the anatomy introduction to the lungs – but I don’t see how the histology part is relevant to the project &lt;br /&gt;
* The abnormal development section was well-written and seemed like the group had done their research &lt;br /&gt;
* The current research section is still empty &lt;br /&gt;
* I liked the development timeline with the historical discoveries. But I think the development is the key stone of the project and therefore it would be nice if it had is own section instead of being the table. But the context itself was good&lt;br /&gt;
* I think the conducting system section is good and I like how you referred to the signalling processes which is also well described. &lt;br /&gt;
* Some sections still need referencing&lt;br /&gt;
* I liked that you included videos in your project&lt;br /&gt;
&lt;br /&gt;
---&lt;br /&gt;
&lt;br /&gt;
Introduction could be longer, briefly introduce what you are going to discuss in this project page. The drawings are nice but could have been better if they were darker and coloured. In the glossary section, everyone do this as you go with your part as there are lots of technical terms. With those pictures included on the page, give them a name e.g. Figure 1, figure 2 etc. and then state them in the text where you would like the readers to see. As seen in the lung cardiovasculature and lung history section, it starts off with “this diagram”, the diagram should be indicated for example: Figure 1 shows…, or the diagram (figure 1) on the right shows … etc. The lung history and structure of respiratory network section are not referenced. The developmental timeline is well presented with both text and images, well referenced, and constructed nicely in the table. In the current understanding, summaries of journal articles and their findings would be beneficial. With animal models, it needs to be referenced and include a few figures. Image showing each of the abnormality in development is a bonus as well. In the other hand, the texts in the abnormal section are nice written, easy to understand and referenced well which show a lot of researches have put into this.&lt;br /&gt;
&lt;br /&gt;
---&lt;br /&gt;
&lt;br /&gt;
The anatomy, histology and cardiovasculature sections are written and structured very well. The figures are direct, clear and enhance the text. The bolded words highlight anatomy specific for the lung and would be wonderful for the future glossary. Timeline is formatted extremely well and the level of detail coupled with the figures used is excellent. The structure of the respiratory network and the development signalling pathways are again done very well but would benefit from deeper referencing. The inclusion of short movies is entertaining and a helpful learning tool. Abnormal development was covered extensively and referenced well. Overall there was a cohesive writing style and approach to the topics, which flowed very well and created an engaging page.&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311322</id>
		<title>User:Z5113034</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311322"/>
		<updated>2017-10-12T02:34:04Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Group 5 */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341ProjectGroup2017table}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Here is the [[Student Page]] demonstration page I showed in the Practical class.&lt;br /&gt;
&lt;br /&gt;
Use this page to practice editing and don't forget to add a topic to the [[2017 Group Project 6]] page.&lt;br /&gt;
&lt;br /&gt;
[[Student Page]] [[Student Page]] [[Student Page]]&lt;br /&gt;
&lt;br /&gt;
The [https://docs.google.com/document/d/1Z0ui9HkyBsitcQuD5YYYp4JyTgSHmZFy6MoaOHyKAlI/edit group discussion]&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
{{2017ANAT2341 footer}}&lt;br /&gt;
&lt;br /&gt;
=Peer Reviews=&lt;br /&gt;
==Group 1==&lt;br /&gt;
The most obvious flaw was the lack of polish in formatting of some of the page. Bullet points are only so useful when it comes to writing a wiki page, instead of taking notes. The page is unfinished, but, the content included especially in the &amp;quot;Development of Cerebral Cortex&amp;quot; and &amp;quot;Abnormalities associated with Cerebral Cortex Development&amp;quot; was extensive and well done. The large table that linked the development with the time period was very useful and the choice of bolding key words allowed the main idea in the paragraph to be quickly understood from a glance. The use of images very much enhanced the descriptions and checker-like the layout of the different abnormalities was refreshing. Some subheadings, such as the Anatomy and Function of the cerebral cortex, could be elaborated on but the overall structure of the page is logical and fluid, and the writing is clear and concise without being superficial.&lt;br /&gt;
&lt;br /&gt;
==Group 2==&lt;br /&gt;
The introduction is clear and well-thought-out; simple enough that the layman can understand but comprehensive enough to lead logically into the more extensive information on the page. Perhaps a discussion of the kidney's function ought to be included with the description of kidney structure. Kidney development; the choice of that particular style of formatting runs a risk of not tying the development with the timeline but the small table at the top serves well to stop that, even if it is a little of a hassle moving back and forth to keep up. The content was well-written and appropriate in voice and depth of knowledge. Visually well-presented with figures appropriately explained. Developmental abnormalities were covered well, and although bullet points may not be the best way to present the information, it allowed for the key points to be understood very quickly and effectively. The transition from topic to topic was logical and flowed appropriately. Some aspects of the page must of course be filled out but overall a well-rounded, well-structured and informative page. Well done.&lt;br /&gt;
&lt;br /&gt;
==Group 3==&lt;br /&gt;
Overall a very in-depth page with most of the required subjects covered. Some general notes; the figures would have benefited from appropriate captions but were helpful nonetheless. Referencing and overall visual formatting could be improved. The page is written well and enjoyable to read. &lt;br /&gt;
&amp;quot;Primary heart field and heart tube formation&amp;quot; could benefit from a diagram or figure since it is a lot of text that could be hard to conceptualise. The signalling processes are explained very well and in deep detail. Just a note though; the addressing of so many different variables in the signalling is a little confusing and hard to follow. Perhaps a more condensed response might be a little more straightforward. The diagram of the signalling pathways under &amp;quot;Wnt Signalling&amp;quot; was likewise hard to follow, and no key was given. Current Research and Animal Models were covered well and the explanation for their research and the key results highlighted were fascinating. Abnormal development was likewise addressed very well and the glossary of terms was very much appreciated.&lt;br /&gt;
&lt;br /&gt;
==Group 4==&lt;br /&gt;
The &amp;quot;Anatomy of the eye&amp;quot; was addressed very well, and the figures were very useful. However, significant aspects discussed in the Anatomy section were not present in the figures and could leave readers confused, for example, when all the muscles responsible for ocular movement were listed but not illustrated; there would be no need to list the proper names of all the muscles. Other than that the section was written well, merging description of form with explanation of function. The tables used in &amp;quot;Eye Development&amp;quot; were also gratifyingly direct, although some elaboration could improve the notes. From what is completed in the development of the &amp;quot;Components&amp;quot; the writing is engaging and the content is appropriately thorough. A diagram or figure would add to the good content. Congenital anomalies are a little brief but the images and table worked well in terms of formatting and visual appeal. Overall good job, would have appreciated a little more completion. &lt;br /&gt;
&lt;br /&gt;
==Group 5==&lt;br /&gt;
The anatomy, histology and cardiovasculature sections are written and structured very well. The figures are direct, clear and enhance the text. The bolded words highlight anatomy specific for the lung and would be wonderful for the future glossary. Timeline is formatted extremely well and the level of detail coupled with the figures used is excellent. The structure of the respiratory network and the development signalling pathways are again done very well but would benefit from deeper referencing. The inclusion of short movies is entertaining and a helpful learning tool. Abnormal development was covered extensively and referenced well. Overall there was a cohesive writing style and approach to the topics, which flowed very well and created an engaging page.&lt;br /&gt;
&lt;br /&gt;
=Subheading=&lt;br /&gt;
[[File:Chicken embryo E-cad and P-cad gastrulation.png|500px]]&lt;br /&gt;
&lt;br /&gt;
embryo&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/sites/gquery?term=embryo ''embryo'']&lt;br /&gt;
&lt;br /&gt;
notochord&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/pubmed?term=notochord ''notochord'']&lt;br /&gt;
&lt;br /&gt;
References&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;28786202&amp;lt;/pubmed&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311310</id>
		<title>User:Z5113034</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311310"/>
		<updated>2017-10-12T02:09:41Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Reviews */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341ProjectGroup2017table}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Here is the [[Student Page]] demonstration page I showed in the Practical class.&lt;br /&gt;
&lt;br /&gt;
Use this page to practice editing and don't forget to add a topic to the [[2017 Group Project 6]] page.&lt;br /&gt;
&lt;br /&gt;
[[Student Page]] [[Student Page]] [[Student Page]]&lt;br /&gt;
&lt;br /&gt;
The [https://docs.google.com/document/d/1Z0ui9HkyBsitcQuD5YYYp4JyTgSHmZFy6MoaOHyKAlI/edit group discussion]&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
{{2017ANAT2341 footer}}&lt;br /&gt;
&lt;br /&gt;
=Peer Reviews=&lt;br /&gt;
==Group 1==&lt;br /&gt;
The most obvious flaw was the lack of polish in formatting of some of the page. Bullet points are only so useful when it comes to writing a wiki page, instead of taking notes. The page is unfinished, but, the content included especially in the &amp;quot;Development of Cerebral Cortex&amp;quot; and &amp;quot;Abnormalities associated with Cerebral Cortex Development&amp;quot; was extensive and well done. The large table that linked the development with the time period was very useful and the choice of bolding key words allowed the main idea in the paragraph to be quickly understood from a glance. The use of images very much enhanced the descriptions and checker-like the layout of the different abnormalities was refreshing. Some subheadings, such as the Anatomy and Function of the cerebral cortex, could be elaborated on but the overall structure of the page is logical and fluid, and the writing is clear and concise without being superficial.&lt;br /&gt;
&lt;br /&gt;
==Group 2==&lt;br /&gt;
The introduction is clear and well-thought-out; simple enough that the layman can understand but comprehensive enough to lead logically into the more extensive information on the page. Perhaps a discussion of the kidney's function ought to be included with the description of kidney structure. Kidney development; the choice of that particular style of formatting runs a risk of not tying the development with the timeline but the small table at the top serves well to stop that, even if it is a little of a hassle moving back and forth to keep up. The content was well-written and appropriate in voice and depth of knowledge. Visually well-presented with figures appropriately explained. Developmental abnormalities were covered well, and although bullet points may not be the best way to present the information, it allowed for the key points to be understood very quickly and effectively. The transition from topic to topic was logical and flowed appropriately. Some aspects of the page must of course be filled out but overall a well-rounded, well-structured and informative page. Well done.&lt;br /&gt;
&lt;br /&gt;
==Group 3==&lt;br /&gt;
Overall a very in-depth page with most of the required subjects covered. Some general notes; the figures would have benefited from appropriate captions but were helpful nonetheless. Referencing and overall visual formatting could be improved. The page is written well and enjoyable to read. &lt;br /&gt;
&amp;quot;Primary heart field and heart tube formation&amp;quot; could benefit from a diagram or figure since it is a lot of text that could be hard to conceptualise. The signalling processes are explained very well and in deep detail. Just a note though; the addressing of so many different variables in the signalling is a little confusing and hard to follow. Perhaps a more condensed response might be a little more straightforward. The diagram of the signalling pathways under &amp;quot;Wnt Signalling&amp;quot; was likewise hard to follow, and no key was given. Current Research and Animal Models were covered well and the explanation for their research and the key results highlighted were fascinating. Abnormal development was likewise addressed very well and the glossary of terms was very much appreciated.&lt;br /&gt;
&lt;br /&gt;
==Group 4==&lt;br /&gt;
The &amp;quot;Anatomy of the eye&amp;quot; was addressed very well, and the figures were very useful. However, significant aspects discussed in the Anatomy section were not present in the figures and could leave readers confused, for example, when all the muscles responsible for ocular movement were listed but not illustrated; there would be no need to list the proper names of all the muscles. Other than that the section was written well, merging description of form with explanation of function. The tables used in &amp;quot;Eye Development&amp;quot; were also gratifyingly direct, although some elaboration could improve the notes. From what is completed in the development of the &amp;quot;Components&amp;quot; the writing is engaging and the content is appropriately thorough. A diagram or figure would add to the good content. Congenital anomalies are a little brief but the images and table worked well in terms of formatting and visual appeal. Overall good job, would have appreciated a little more completion. &lt;br /&gt;
&lt;br /&gt;
==Group 5==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Subheading=&lt;br /&gt;
[[File:Chicken embryo E-cad and P-cad gastrulation.png|500px]]&lt;br /&gt;
&lt;br /&gt;
embryo&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/sites/gquery?term=embryo ''embryo'']&lt;br /&gt;
&lt;br /&gt;
notochord&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/pubmed?term=notochord ''notochord'']&lt;br /&gt;
&lt;br /&gt;
References&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;28786202&amp;lt;/pubmed&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311308</id>
		<title>User:Z5113034</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311308"/>
		<updated>2017-10-12T02:09:07Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Reviews */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341ProjectGroup2017table}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Here is the [[Student Page]] demonstration page I showed in the Practical class.&lt;br /&gt;
&lt;br /&gt;
Use this page to practice editing and don't forget to add a topic to the [[2017 Group Project 6]] page.&lt;br /&gt;
&lt;br /&gt;
[[Student Page]] [[Student Page]] [[Student Page]]&lt;br /&gt;
&lt;br /&gt;
The [https://docs.google.com/document/d/1Z0ui9HkyBsitcQuD5YYYp4JyTgSHmZFy6MoaOHyKAlI/edit group discussion]&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
{{2017ANAT2341 footer}}&lt;br /&gt;
&lt;br /&gt;
=Peer Reviews=&lt;br /&gt;
==Group 1==&lt;br /&gt;
The most obvious flaw was the lack of polish in formatting of some of the page. Bullet points are only so useful when it comes to writing a wiki page, instead of taking notes. The page is unfinished, but, the content included especially in the &amp;quot;Development of Cerebral Cortex&amp;quot; and &amp;quot;Abnormalities associated with Cerebral Cortex Development&amp;quot; was extensive and well done. The large table that linked the development with the time period was very useful and the choice of bolding key words allowed the main idea in the paragraph to be quickly understood from a glance. The use of images very much enhanced the descriptions and checker-like the layout of the different abnormalities was refreshing. Some subheadings, such as the Anatomy and Function of the cerebral cortex, could be elaborated on but the overall structure of the page is logical and fluid, and the writing is clear and concise without being superficial.&lt;br /&gt;
&lt;br /&gt;
==Group 2==&lt;br /&gt;
The introduction is clear and well-thought-out; simple enough that the layman can understand but comprehensive enough to lead logically into the more extensive information on the page. Perhaps a discussion of the kidney's function ought to be included with the description of kidney structure. Kidney development; the choice of that particular style of formatting runs a risk of not tying the development with the timeline but the small table at the top serves well to stop that, even if it is a little of a hassle moving back and forth to keep up. The content was well-written and appropriate in voice and depth of knowledge. Visually well-presented with figures appropriately explained. Developmental abnormalities were covered well, and although bullet points may not be the best way to present the information, it allowed for the key points to be understood very quickly and effectively. The transition from topic to topic was logical and flowed appropriately. Some aspects of the page must of course be filled out but overall a well-rounded, well-structured and informative page. Well done.&lt;br /&gt;
&lt;br /&gt;
==Group 3==&lt;br /&gt;
Overall a very in-depth page with most of the required subjects covered. Some general notes; the figures would have benefited from appropriate captions but were helpful nonetheless. Referencing and overall visual formatting could be improved. The page is written well and enjoyable to read. &lt;br /&gt;
&amp;quot;Primary heart field and heart tube formation&amp;quot; could benefit from a diagram or figure since it is a lot of text that could be hard to conceptualise. The signalling processes are explained very well and in deep detail. Just a note though; the addressing of so many different variables in the signalling is a little confusing and hard to follow. Perhaps a more condensed response might be a little more straightforward. The diagram of the signalling pathways under &amp;quot;Wnt Signalling&amp;quot; was likewise hard to follow, and no key was given. Current Research and Animal Models were covered well and the explanation for their research and the key results highlighted were fascinating. Abnormal development was likewise addressed very well and the glossary of terms was very much appreciated.&lt;br /&gt;
&lt;br /&gt;
==Group 4==&lt;br /&gt;
The &amp;quot;Anatomy of the eye&amp;quot; was addressed very well, and the figures were very useful. However, significant aspects discussed in the Anatomy section were not present in the figures and could leave readers confused, for example, when all the muscles responsible for ocular movement were listed but not illustrated; there would be no need to list the proper names of all the muscles. Other than that the section was written well, merging description of form with explanation of function. The tables used in &amp;quot;Eye Development&amp;quot; were also gratifyingly direct, although some elaboration could improve the notes. From what is completed in the development of the &amp;quot;Components&amp;quot; the writing is engaging and the content is appropriately thorough. A diagram or figure would add to the good content. Congenital anomalies are a little brief but the images and table worked well in terms of formatting and visual appeal. Overall good job, would have appreciated a little more completion. &lt;br /&gt;
&lt;br /&gt;
===Subheading===&lt;br /&gt;
[[File:Chicken embryo E-cad and P-cad gastrulation.png|500px]]&lt;br /&gt;
&lt;br /&gt;
embryo&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/sites/gquery?term=embryo ''embryo'']&lt;br /&gt;
&lt;br /&gt;
notochord&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/pubmed?term=notochord ''notochord'']&lt;br /&gt;
&lt;br /&gt;
References&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;28786202&amp;lt;/pubmed&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_4&amp;diff=311306</id>
		<title>Talk:2017 Group Project 4</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_4&amp;diff=311306"/>
		<updated>2017-10-12T02:09:01Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
&lt;br /&gt;
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== Group talk ==&lt;br /&gt;
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=== To do ===&lt;br /&gt;
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* An introduction of what the page will go through&lt;br /&gt;
* Make sure all the required subjects are in the project [[ANAT2341 Lab 1]]&lt;br /&gt;
* Glossary list&lt;br /&gt;
* Maybe add videos&lt;br /&gt;
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=== Work sites ===&lt;br /&gt;
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z5177670: Lens, Ciliary Body, Iris, Cornea (http://www.sciencedirect.com/science/article/pii/S1877117315000642, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1298807/pdf/taos00013-0203.pdf)&lt;br /&gt;
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z5075778: Extraocular muscles and Retina&lt;br /&gt;
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z5117343: Congenital Anomalies, Treatment, Diagnosis&lt;br /&gt;
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z5075309: Cornea, Aqueous Chambers, Choroid and Sclera, Lacrimal Glands (&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;23528534&amp;lt;/pubmed&amp;gt;&amp;lt;/ref &amp;gt;)&lt;br /&gt;
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=== Timeline ===&lt;br /&gt;
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I tried making a timeline of how I understand the events in eye development. Please add components or change in the timeline if you disagree - it's just a draft :-) &lt;br /&gt;
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=== Eyes development===&lt;br /&gt;
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'''Articles for general eye development''' &lt;br /&gt;
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I found a few articles about the general eye development and thought I wanted to share them with you all. If we find some good references, please share it here on the page, so we can help each other :-) &lt;br /&gt;
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https://www.ncbi.nlm.nih.gov/books/NBK10024/ - Development of the Vertebrate Eye&lt;br /&gt;
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3504437/ - Eye Development and Retinogenesis&lt;br /&gt;
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http://www.sciencedirect.com/science/article/pii/0014483575900755?via%3Dihub - The prenatal development of the human eye&lt;br /&gt;
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https://www.ncbi.nlm.nih.gov/pubmed/10627820 - Lens development.&lt;br /&gt;
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http://www.sciencedirect.com/science/article/pii/S0012160606014898?via%3Dihub - FGF-mediated induction of ciliary body tissue in the chick eye&lt;br /&gt;
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http://dev.biologists.org/content/141/23/4432.long - The cellular and molecular mechanisms of vertebrate lens development&lt;br /&gt;
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http://www.sciencedirect.com/science/article/pii/S0014483510000448 - On the growth and internal structure of the human lens&lt;br /&gt;
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http://www.sciencedirect.com/science/article/pii/S1877117315000642 - Chapter Four - Corneal Development: Different Cells from a Common Progenitor&lt;br /&gt;
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http://www.annualreviews.org/doi/full/10.1146/annurev.cellbio.17.1.255?url_ver=Z39.88-2003&amp;amp;rfr_id=ori%3Arid%3Acrossref.org&amp;amp;rfr_dat=cr_pub%3Dpubmed (Need permission for this article)&lt;br /&gt;
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http://onlinelibrary.wiley.com.wwwproxy1.library.unsw.edu.au/doi/10.1002/ajmg.a.35713/full&lt;br /&gt;
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https://www.aao.org/eye-health/diseases/what-is-coloboma&lt;br /&gt;
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http://jmg.bmj.com/content/jmedgenet/41/12/881.full.pdf&lt;br /&gt;
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3126628/&lt;br /&gt;
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5581554/&lt;br /&gt;
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https://www.ncbi.nlm.nih.gov/pubmed/11826019/&lt;br /&gt;
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==Suggested Starting Places==&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 4 below are some starting places.&lt;br /&gt;
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{{Vision Links}}&lt;br /&gt;
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PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Eye+Development ''Eye Development''] | [http://www.ncbi.nlm.nih.gov/pubmed?term=Vision+Development ''Vision Development'']&lt;br /&gt;
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BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Eye+Development ''Eye Development'']&lt;br /&gt;
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Recent papers&lt;br /&gt;
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&amp;lt;pubmed limit=5&amp;gt;Eye+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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&amp;lt;references/&amp;gt;&lt;br /&gt;
=Peer Review=&lt;br /&gt;
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This is a well structured page, that approaches the eye from the basics. I like that the anatomy and underlying physiology of the eye is established before the developmental processes. Overview is brief and to the point, and the Embryonic Contributions table is an important aspect. Iris development could be expanded on, and more journal article images could be included, to show a wider range of sources were used. The &amp;quot;Opac figure&amp;quot; file does not have the correct Copyright notice. Images and tables could include a small description directly under (or above) for ease of reading. The student drawn images are well included, but are slightly hard to follow due to their small size and lack of differentiating colour and/or patterning, these images also lack the appropriates Student Image template. &lt;br /&gt;
Subheadings would be more noticeable if they were bigger and not just in bold. An 'animal models in comparison with human development' and 'signalling ' sections would be helpful. There are a range of spelling errors throughout the text, including the &amp;quot;Congenital Abnormalities&amp;quot; title. The page could be improved with an introduction as a lead-in to what the project with discuss, and a historical discoveries section to understand the studies that lead to our current understanding. However, on the whole this is a very good page!&lt;br /&gt;
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Overall a great start on the wiki, the information is well presented however it still needs a bit more work before the due date. The Anatomy section is particularly good and the breakdown of the anatomy of the different sections of the eye, helps with interpretation and is really helpful. The use of images is really good, providing a visual reference point and further enhancing the information provided. It would be good to have a brief introduction on the page before the development and consequent information is written. Expand and complete the information of the development of the different parts of the eye, however the information currently there is very well written and understandable. Elaborate on the abnormalities and maybe you could include the pictures in the table, or expand on them outside of the table and have the pictures on the side. Complete the sections of the Carnegie table. Overall, it is a great start.&lt;br /&gt;
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The team should provide a brief description of what the images are on their page so readers will understand immediately what it is. The team could use some images to show Caregie Stages, but the section is yet to be completed. An explanation of the ‘Timeline of embryonic development’ table would be beneficial to help readers understand what the table is explaining. More resources could be used for the Anatomy of the Adult Eye so that the team has shown to have used a variety of sources and have done plenty of research. There are incomplete sections. The team could include current research and animal models as extra subheadings. &lt;br /&gt;
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Subheadings and content that have been used show a good understanding of the topic area. The team has used their own images to display their learning. The references have been correctly cited. The use of tables helps readers understand what the content is about, and is easy to follow for readers. Some of the images have been cited correctly; they have references, copyright statements and the Student Image template. However, some of the images don’t have the Student Image template. The abnormalities subheading was done well with the use of images and references.&lt;br /&gt;
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'''Peer review project 4:''' &lt;br /&gt;
* The project does not feel like it is finished. A lot of work still needs to be done, and some of the subheadings like retina, cornea, eyelids, lacrimal glands etc is still empty. &lt;br /&gt;
* I did not find any sections describing signalling, research or future questions and animal models. I miss some more research content and a research angle to the project. &lt;br /&gt;
* The few parts of the development of the eye components which has been written was good. It was easy to understand and had good referencing. &lt;br /&gt;
* In general, the project could use more pictures to support the text. &lt;br /&gt;
* The anatomy part of the project was good. The drawing made it easier to understand, even though the picture captions and numbers are missing. I did not have any difficulties understanding it and they wrote it in a very clear way. &lt;br /&gt;
* I liked the overview of the eye development, it made it clear what is happening when, which cells comes from which germ layer and the Carnegie stage is a nice adding, even though it is not finished. &lt;br /&gt;
* The abnormal development section is far from finished. I think it is an important part of the project and it would improve the project if the anomalies where describe more in depth and not in a table. &lt;br /&gt;
* The glossary section was empty as well.&lt;br /&gt;
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Overall the project page looks good. I like that you have used a mix of student drawn diagrams and also paper derived ones. However, I do think that the ‘anterior eye’ drawing could be a little clearer, as it is a hard to tell what label corresponds to what. Also, the referencing for these I presume the original diagrams are from an anatomy book or something, this should be cited as a ‘based on…’&lt;br /&gt;
Stage 21 and 22 are missing and should be filled in with the accompanying information. &lt;br /&gt;
Having a number of tables really helps convey some of the information in a succinct manner, I particularly like this approach in the congenital abnormalities section. &lt;br /&gt;
In the ‘development of the eye components’ section some visual aids would be helpful otherwise there is just going to be a lot of text, and in order to keep the reader engaged, pictures or even animations would really help.&lt;br /&gt;
Could have a wider list of references, but I imagine as information is added so will these be. &lt;br /&gt;
Well done! &lt;br /&gt;
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Has good structure, and overall a good feel in the developmental process of the eye. However the page seems to be unfinished, since there are a lot of blank areas under the subheadings (Retina, Cornea, Aqueous Chambers, Choroid and Sclera, Eyelids, Lacrimal Glands) and tables. Use of tables (i.e Carnegie stages) were very helpful and makes the content easier to understand. Hand drawn images were also very well done and aids in understanding the content, however they need to be labelled with &amp;quot;taken from ...&amp;quot;. Congenital anomalies section lacks information, perhaps each anomaly deserves its own subheading since it is a quite important part of the topic. Although references were done correctly, a lot of parts seem to be missing citations (&amp;quot;Supporting Structures&amp;quot; and &amp;quot;Anterior Structure&amp;quot; under Anatomy). Overall, well done so far!&lt;br /&gt;
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The developmental timetable and “Development of the eye components” have very clear information that explains the embryology of eye development. However, these sections are currently unfinished and could benefit from some supporting images. Either information could be filled in for Stages 21 and 22, or the 2 rows should be deleted. The event description of Stage 23 “The face is beginning to look human,” is a slightly odd and subjective statement for the table. &lt;br /&gt;
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The “Anatomy of the Adult Eye” has great drawn pictures to go along with the descriptions. A picture of the supporting structures of the eye would also be beneficial but is not necessary. These pictures need summaries when clicking on them and the files should be renamed from the series of numbers they are currently labeled as. &lt;br /&gt;
The “Embryonic Contributions” table is a good, quick, clear way to summarize eye development. You may want to move this section before the developmental timetable along with the “Short overview” description. Both the “Short overview” and “Anatomy of the Adult Eye” sections could be broken up from the long paragraph format to some bulleted information with shorter paragraphs to make the information easier to read and understand. In “Extraocular muscles,” it is mentioned that the inferior oblique muscle has a distinct embryonic origin but that origin is not mentioned. &lt;br /&gt;
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The table for “Congenital Abnormalities” is a solid way to present the information. The descriptions and epidemiology are short and clear. This section would benefit from another column describing the embryonic origin of these issues and maybe 2 or more abnormalities added to the table. &lt;br /&gt;
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There are several headings that are either blank or unfinished and some basic grammatical and spelling errors throughout the project. Some picture files should be renamed and a quick summary should be added. A couple more pictures could be added to support the information. A description of the studies that led to the discovery of the information on this page could also be added to improve the project. &lt;br /&gt;
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The page has an unfinished feel to it due to the lack of introduction, empty subheadings towards the end of the page and &amp;quot;this section is not done yet&amp;quot; written. Abnormalities is spelt incorrectly. Clever use of self drawn diagrams to avoid copyright issues, however I think it's better to use actual images from journals because some images are hard to understand, hard to read and don't look accurate- i was unaware the sclera, choroid and retina took up so much space in the vitreous humour. Id also advise to add images to show the developments of the embryonic eye, making it more appealing for the reader. Also adding images to the &amp;quot;Development of the eye components&amp;quot; section.&lt;br /&gt;
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Firstly those pointers under the heading Eye Development need to be deleted; I think they're just suggestions from Mark but if not you already have the subheadings at the top? An introduction to the human eye might ease into the topic a little better. You have done the anatomy of the adult eye really really well. The images you've drawn yourself to outline the structure is really good and there is an abundance of information, so I think this part is great! The timelines need to be completed, as you've stated otherwise they would be good timelines to follow as a basic structure for someone learning about fetal eye development. The information in the short overview is really good, however overview of what exactly? Make the heading more specific. The development of the eye components is really good however isn't complete. This section could, however, be improved by adding some images in to show the region of the eye you're talking about. The abnormalities section is good, however, I think you could refer to the figure instead of just having them below and a little more information on the description or consequences of the diseases would add more substance. The glossary also needs to be completed. Your referencing seems to be correct throughout. Overall good work the page just needs a few changes and more information!&lt;br /&gt;
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Reading through this page was very interesting and informative however I have a few points that could be adjusted to improve on your page. When inserting an image, adding a figure and brief description on the images would be useful. The timeline is good but there is no reference so it definitely needs one. When reading through all the other tables, references need to be used more as it isn't that easy to figure out what articles you have used to get your information. More work needs to be done to fill the headings under development of eye components and if  more images were added it would be useful. Abnormalities could have a bit more of an explanation written as well. Your wiki page is looking good, I would suggest a heading on animal models would provide some good information and fit well with your page! I also haven’t read anything that tells us about signaling, this should have its own heading and should be explained quite well as it is an important part of development. With your figures, it would be nice if you referred to them throughout your text more, and integrated them with the headings. Although this page is a work in progress, the information written is useful and easy to understand.&lt;br /&gt;
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This page jumps straight into the “anatomy of the adult eye”. However, I would suggest a brief introduction (just a paragraph) on the eye, its development, its function and what this page will explore. I think the text under the subheading “anatomy of the adult eye” could be cut down or at least altered. For example, you would be good to bold some words so that they stand out – especially if they are mentioned in the diagrams. The timeline is a very brief overview of development which is probably good considered you have a more detailed table for the Carnegie stages. I would suggest that you add another column for images for the Carnegies stages once you’ve completed it.&lt;br /&gt;
I think it’s good that you went into the specific development of the eye components but I think it would be more interesting if you added an image or diagram for each component. Also, you still need to complete the majority of the components in this section and when you do I would suggest you keep it at one to two paragraphs. The subheading, “Congenital anomalies”, is nice and succinct with the main anomalies outlined and images to visually represent each. However, I think here there is a bit of underrepresentation of the abnormalities. I feel like you could go into some more detail about each abnormality as other groups have done. The references could be extended to about 25 once you’ve filled in the empty parts.&lt;br /&gt;
You might also want to add a “current research” subheading as it is relevant and shows how our understanding and knowledge of the eye’s development is always expanding.&lt;br /&gt;
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Overall the page looks neat in the arrangement of the information. Before the anatomy of the eye, maybe a short paragraph on the general information of the eye could be included to have a good introduction to the project page. For the anatomy of the eye, there is a fair amount of information and good images to support the information. If the group wants to take this section a little further, they could include histological images. For the images that were drawn, perhaps a brief description could be included. For the overview of the eye development, I really like how there was a general table foe the different weeks of development and then another following table with the carniage stages. This helped the reader to have a broad overview before narrowing down to the specifics. However, I think images re needed to understand the stages better because its hard to picture the development without any pictorial aid. Also, I think the headings and subheadings for this part may need to be modified. Maybe you can start off with “Development of the Eye”. and instead of “short overview”, you can change it to “An overview of Eye Development”. Also, all the information was taken from only one source so maybe more articles could be sourced in order to have more credibility. &lt;br /&gt;
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For the development of the eye components, the content is sufficient and concise but more images are necessary as some parts gets a little confusing. There is a good amount of references for this section. For the congenital abnormalities, the table is a good way to present the information. However, more information about the abnormalities is needed under the description column. As for the images, I think maybe you could create another column and add the image to that row for each abnormality. This would give the table a more complete look and the section will be really good. There is also  good amount of references and the images are correctly referenced and the copyright statements are included so that’s well done.&lt;br /&gt;
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Overall, this wikipage is pretty incomplete. However, that has been mentioned several times by the team, so i'm sure they will add on more after the peer review. The page is very neat and the text was quite concise. An introduction could be helpful to introduce what is an eye and what it does in the human body. In the anatomy of the adult eye, it was good that there were images of drawings to show the different parts of the eye, perhaps the drawings could be more clearly labelled with a thinner pen/pencil. Also a description of the image would be good as well. This section was well referenced. For the overview of eye develoment, I like the use of tables as it made it very easy to understand the content. The image (Figure 1.) was also well described and had appropriate copyright information. For the headings of this section, some could be changed such as 1.2 Eye Development, 1.2.1 Timeline of Eye Embryology,  1.2.4 Brief Outline/Description of the Eye Development. The portion on development of the eye components is incomplete, however for the parts that were there, there was not too much text and appropriate referencing. Pictures could be used in this section to improve it. For the congenital anomalies, I like the use of the table for ease of reading and understanding. Perhaps a more detailed description could be included. Also maybe the images could be added into the table as another column to make it neater. Good job so far, I think with some alterations and once they add the rest of the page, it would be a good wikipage! :)&lt;br /&gt;
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The structure and layout of this page is clear and concise. At first glance it does seem quite brief, however it is understandable that the project is still under completion. An introduction section with an overall introduction of eye development would improve the flow of the project. The use of tables and diagrams make the page attractive and more appealing to read. I like the use of hand drawn diagrams, however they still need to be labeled. Many sections such as development of the eye components have large sections of text which aren’t appealing to read and the use of youtube videos, diagrams or collapsible videos could improve this. The section ‘overview of eye development’ is very informative and gives a good summary of what will later be described in detail. Some sections also have minimal referencing and this could be worked on. I also think an overall large title of ‘The eye’ at the top of the page would be appealing. Overall, well done this page is almost complete and your information is relevant and informative.&lt;br /&gt;
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Anatomy of the adult eye is the shining feature of this page because it is very detailed and is balanced by personal images (one or two web images also might be helpful).  I like that the group used a lot of tables throughout the sections because it helps organize the essential information all into one--many need references however.  For example, the abnormalities section (fix spelling) is done very well; the table is well organized and nicely arranged so that the images are labeled at the bottom instead of interrupting the table itself.  Overall, there is a simple structure to the page that makes the page easy to read and it has a nice flow. There is missing information from stage 21-23 in the Carnegie stages table, as well as from parts of the eye components.  Development of the eye components is informative but could be improved by adding visuals in each section.  While there is a lot of helpful detail for overall eye anatomy, some information on signaling, current research, future questions and animal models would make it better. An introduction would also be beneficial.&lt;br /&gt;
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Introduction section is missing. It is better to start off introducing what you are going to discuss about briefly. The developmental timeline is informative.&lt;br /&gt;
Developmental signaling pathway of the eye is missing. Would be beneficial if a brief mechanism is discussed. &lt;br /&gt;
In each part of the eye development, consider putting labeled pictures for readers to navigate back to see where and what they are looking at, as there are many structures written in the text. Also, start building the glossary terms as you go. Some of the subheadings under this section are not done; I assume they will be later. &lt;br /&gt;
With the congenital anomalies, i think it should be congenital abnormalities. Tackle some details for each of the abnormalities, mention the causes, how it happens, how common it is in Australia, briefly touch on how severe it is and how to treat them if possible, what are the underlying mechanism for this. This section needs a lot more information.&lt;br /&gt;
Current research and animal model subheadings are not seen, should have this in the project. It is essential to include 2-3 current research journals on the eyes.&lt;br /&gt;
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&amp;lt;b&amp;gt;Strengths: &amp;lt;/b&amp;gt; &amp;lt;br&amp;gt;&lt;br /&gt;
•	Authors of the wiki page have covered a variety of topics regarding eye development. It was great how the authors have included a general overview of eye development followed by a description of specific components within the eye, this definitely helped add depth to your wiki page was also satisfying criteria 1 of the assessment outline. &amp;lt;br&amp;gt;&lt;br /&gt;
•	The authors of the page have also included a number of images and tables to help present information in a more clear and concise manner. The use of a table to describe the stages of eye development was excellent as it helped simplify the entire process (criteria 2). &amp;lt;br&amp;gt;&lt;br /&gt;
•	It was great to see hand drawn diagrams within the wiki page. These diagrams helped simplify the overall anatomy of the eye to audiences who may not have a background in science, thus it is excellent that the page focuses on teaching at the peer level (criteria 4). &amp;lt;br&amp;gt;&lt;br /&gt;
•	It is also great that the authors have included a glossary to help define words which may not be familiar with all audiences. &amp;lt;br&amp;gt;&lt;br /&gt;
&amp;lt;b&amp;gt;Areas of improvement: &amp;lt;/b&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	To improve, the authors may have included a greater number of images whilst also including videos. More images may have been included under the heading “development of the eye components” to help reinforce the information already included. In addition, certain subheadings under this heading may include a greater description. For example, the subheading “Iris” may include a greater description of how the iris comes to develop. In addition, the authors of this wiki page may have also included videos as another visual tool to help explain certain processes described. &amp;lt;br&amp;gt;&lt;br /&gt;
•	 In addition, it appears that certain areas of the wiki page do not include references to cite certain portions of information included. For example, the section about the anatomy of the eye has utilized a small number of references. In order to completely satisfy criteria 3 of this assessment, authors may wish to correctly cite information included within this section.  &amp;lt;br&amp;gt;&lt;br /&gt;
•	The authors of the wiki page may wish to conduct further research into the subheading “congenital anomalies”. In doing so, a possible area that may be researched is treatment currently available to tackle these anomalies (for example different types of stem cell research being conducted” (criteria 5).  &lt;br /&gt;
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This peer review is based on the relevant dot points of the ‘Group Assessment Criteria’, as well as subheadings suggested by Mark. This information can be found on the student page. &lt;br /&gt;
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{| border=&amp;quot;1&amp;quot; align=&amp;quot;left&amp;quot;&lt;br /&gt;
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|Criteria&lt;br /&gt;
|Strengths&lt;br /&gt;
|Weaknesses&lt;br /&gt;
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| 1. The choice of content shows a good understanding of the topic area&lt;br /&gt;
| The ‘anatomy of the eye’ clearly conveys background information regarding the eye, and makes a nice introduction to the wiki page.&lt;br /&gt;
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The embryology timeline, even if not finished yet, is very detailed and informative. This gives the reader an overall understanding of the development of the eye.&lt;br /&gt;
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The ‘abnormal development’ section, although short, conveys information very clearly and summarises abnormal conditions well. &lt;br /&gt;
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The well-structured sub headings of the wiki page make the information easier to follow and link together. &lt;br /&gt;
| The wiki page is missing several important areas of information:&lt;br /&gt;
*There is no information about key historical discoveries regarding development of the eye.&lt;br /&gt;
*There is no section on animal models used to further understanding on eye development&lt;br /&gt;
*There is no section on current research regarding embryological development of the eye&lt;br /&gt;
*There is no section on developmental signalling processes of the eye &lt;br /&gt;
*There is no section on future questions in research relating to eye development &lt;br /&gt;
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Several sections are largely unfinished (see ‘development of the eye components’). Subheadings have also been added, but lack associated information (see ‘glossary’). &lt;br /&gt;
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|2. Content is correctly cited and referenced&lt;br /&gt;
|There have been attempts at referencing throughout the assignment. A reference list has been produced and appears mostly correct. &lt;br /&gt;
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The reference list is comprised mainly of peer-reviewed primary research articles.  &lt;br /&gt;
&lt;br /&gt;
Images not drawn by students have been referenced correctly (see ‘figure 1’)&lt;br /&gt;
|Overall, referencing throughout the wiki page is poor. Some sections have no in-text citations (see ‘anterior structure’). Other sections have minimal referencing (see ‘short overview’). Remember that any unoriginal ideas or information need to be acknowledged by in-text citations.&lt;br /&gt;
&lt;br /&gt;
Try to obtain information from a variety of sources, rather than just relying on one or two for entire sections (see first paragraph of ‘short overview’).&lt;br /&gt;
&lt;br /&gt;
The student-drawn images have not been referenced correctly. Remember to include the source that ‘inspired’ the drawing. &lt;br /&gt;
&lt;br /&gt;
Some references have been repeated in the reference list (see references 11 and 12).&lt;br /&gt;
|-&lt;br /&gt;
|3. The wiki has an element of teaching at a peer level&lt;br /&gt;
|The information presented is mostly at a level appropriate for peers. The ‘anatomy of the eye’ section provides background information that clarifies information further down the wiki page. &lt;br /&gt;
&lt;br /&gt;
The student-drawn diagrams make some difficult ideas easier to understand. &lt;br /&gt;
&lt;br /&gt;
Many of the tables on the wiki page provide a clear summary of a topic (e.g. for ‘embryonic contributions’)&lt;br /&gt;
|Many of the acronyms and terms used in this assignment are either poorly explained, or not explained at all. Be sure to include a glossary of terms. &lt;br /&gt;
&lt;br /&gt;
Most of the images lack descriptions. Try adding descriptions to make the images easier to understand. In addition, there is a lack of images throughout the page. Remember to include diagrams in other sections, such as in ‘development of the eye components’.&lt;br /&gt;
|-&lt;br /&gt;
|4. Relates the topic and content of the Wiki entry to learning aims of embryology&lt;br /&gt;
|The wiki page addresses several aims of embryology in great detail, such as embryonic development of the eye (see ‘overview of eye development’), and abnormal development. &lt;br /&gt;
|The wiki page lacks content relevant to other aims of embryology, such as current research, key discoveries and developmental signaling processes. Be sure to add some information under these sub-headings. &lt;br /&gt;
|-&lt;br /&gt;
|5. The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic&lt;br /&gt;
|Certain aspects have been well researched, such as development of the eye, and the anatomy of the eye. &lt;br /&gt;
|No links to other pages on the UNSW embryology wiki have been included. Try linking this wiki page to other aspects of the embryology wiki, such as the ‘sensory development’ page. &lt;br /&gt;
&lt;br /&gt;
The reference list currently lacks a wide variety of sources. Using a larger number of reliable sources (i.e. peer reviewed research articles) will ensure that this topic has been well researched.  &lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
Grade: PASS&lt;br /&gt;
&lt;br /&gt;
General Comment: Although some sections of the wiki page have been addressed in great detail, the page is largely unfinished.&lt;br /&gt;
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This page could benefit from an introduction explaining the page and the overall importance of the eye and its development. 'Anatomy of the Adult Eye' has drawn pictures; whilst hand drawing is a great idea I believe these diagrams are a bit hard to understand as the eye is most easily displayed as a 3D model and these diagrams are all 2D. Otherwise, good content. Maybe a structure/function/location/diagram table would be good for this section? 'Overview of eye development' has a couple of sections that still need to be completed; also maybe a bit more detail to the events taking place at each stage would be beneficial. 'Development of the eye components' has good information but I feel that with all the separate parts to be completed there is going to be a lot of text here; again a table may be more useful or the use of pictures as it is getting a bit monotonous to read. 'Congenital Anomalies' this table is very brief and doesn't do each abnormality justice. Figures are useful. This page has a fair bit of work to do; future research questions would be a good subtitle to have and glossary needs to be added to. Overall there is not much to read.&lt;br /&gt;
----&lt;br /&gt;
-	An introduction to the page was absent and preferably would’ve been a good start &lt;br /&gt;
&lt;br /&gt;
-	Anatomy of the eye was very well structured and was elaborated under smaller separate subheadings. Drawings of the eye helped along with the content in this part and different colours also helped decipher the image. It was nice that you included what view of the eye the image was showing. &lt;br /&gt;
&lt;br /&gt;
-	Timeline of embryonic development is a bit brief and possibly elaborating further would have been better. Including a picture here, showing which part of the eye develops in which a progressive timeline would be good.&lt;br /&gt;
 &lt;br /&gt;
-	Carnegie stages was incomplete, which would have been good if it was done with some pictures on the side as well. I liked the table of embryonic contributions as it really helps to simplify things &lt;br /&gt;
&lt;br /&gt;
-	No presence of referencing in Embryonic Contribution or Carnegie Table. &lt;br /&gt;
&lt;br /&gt;
-	A short overview description of the development was nice prior to elaboration of this in the next part “Development of the eye components” &lt;br /&gt;
&lt;br /&gt;
-	The development of eye components was not completed, but information present was good, but could use with some diagrams here to help people picture which part of eye is being explained &lt;br /&gt;
&lt;br /&gt;
-	Some spelling errors were seen, especially for “Congenital Anomalies”… seen throughout the page &lt;br /&gt;
&lt;br /&gt;
-	Nice table for congenital abnormalities, which was nicely summarised and included epidemiology. Would need to elaborate more on each congenital abnormality instead of just a table. &lt;br /&gt;
&lt;br /&gt;
-	Personally, think there should be more references considering the amount of information included on the page. Inclusion of glossary and more pictures/videos would have made this page better. Overall, I think this page is well structured and has made a great use of tabling.&lt;br /&gt;
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The &amp;quot;Anatomy of the eye&amp;quot; was addressed very well, and the figures were very useful. However, significant aspects discussed in the Anatomy section were not present in the figures and could leave readers confused, for example, when all the muscles responsible for ocular movement were listed but not illustrated; there would be no need to list the proper names of all the muscles. Other than that the section was written well, merging description of form with explanation of function. The tables used in &amp;quot;Eye Development&amp;quot; were also gratifyingly direct, although some elaboration could improve the notes. From what is completed in the development of the &amp;quot;Components&amp;quot; the writing is engaging and the content is appropriately thorough. A diagram or figure would add to the good content. Congenital anomalies are a little brief but the images and table worked well in terms of formatting and visual appeal. Overall good job, would have appreciated a little more completion.&lt;br /&gt;
&lt;br /&gt;
---&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311272</id>
		<title>User:Z5113034</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311272"/>
		<updated>2017-10-12T01:18:21Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341ProjectGroup2017table}}&lt;br /&gt;
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&lt;br /&gt;
Here is the [[Student Page]] demonstration page I showed in the Practical class.&lt;br /&gt;
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Use this page to practice editing and don't forget to add a topic to the [[2017 Group Project 6]] page.&lt;br /&gt;
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[[Student Page]] [[Student Page]] [[Student Page]]&lt;br /&gt;
&lt;br /&gt;
The [https://docs.google.com/document/d/1Z0ui9HkyBsitcQuD5YYYp4JyTgSHmZFy6MoaOHyKAlI/edit group discussion]&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
{{2017ANAT2341 footer}}&lt;br /&gt;
&lt;br /&gt;
=Peer Reviews=&lt;br /&gt;
==Group 1==&lt;br /&gt;
The most obvious flaw was the lack of polish in formatting of some of the page. Bullet points are only so useful when it comes to writing a wiki page, instead of taking notes. The page is unfinished, but, the content included especially in the &amp;quot;Development of Cerebral Cortex&amp;quot; and &amp;quot;Abnormalities associated with Cerebral Cortex Development&amp;quot; was extensive and well done. The large table that linked the development with the time period was very useful and the choice of bolding key words allowed the main idea in the paragraph to be quickly understood from a glance. The use of images very much enhanced the descriptions and checker-like the layout of the different abnormalities was refreshing. Some subheadings, such as the Anatomy and Function of the cerebral cortex, could be elaborated on but the overall structure of the page is logical and fluid, and the writing is clear and concise without being superficial.&lt;br /&gt;
&lt;br /&gt;
==Group 2==&lt;br /&gt;
The introduction is clear and well-thought-out; simple enough that the layman can understand but comprehensive enough to lead logically into the more extensive information on the page. Perhaps a discussion of the kidney's function ought to be included with the description of kidney structure. Kidney development; the choice of that particular style of formatting runs a risk of not tying the development with the timeline but the small table at the top serves well to stop that, even if it is a little of a hassle moving back and forth to keep up. The content was well-written and appropriate in voice and depth of knowledge. Visually well-presented with figures appropriately explained. Developmental abnormalities were covered well, and although bullet points may not be the best way to present the information, it allowed for the key points to be understood very quickly and effectively. The transition from topic to topic was logical and flowed appropriately. Some aspects of the page must of course be filled out but overall a well-rounded, well-structured and informative page. Well done.&lt;br /&gt;
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==Group 3==&lt;br /&gt;
Overall a very in-depth page with most of the required subjects covered. Some general notes; the figures would have benefited from appropriate captions but were helpful nonetheless. Referencing and overall visual formatting could be improved. The page is written well and enjoyable to read. &lt;br /&gt;
&amp;quot;Primary heart field and heart tube formation&amp;quot; could benefit from a diagram or figure since it is a lot of text that could be hard to conceptualise. The signalling processes are explained very well and in deep detail. Just a note though; the addressing of so many different variables in the signalling is a little confusing and hard to follow. Perhaps a more condensed response might be a little more straightforward. The diagram of the signalling pathways under &amp;quot;Wnt Signalling&amp;quot; was likewise hard to follow, and no key was given. Current Research and Animal Models were covered well and the explanation for their research and the key results highlighted were fascinating. Abnormal development was likewise addressed very well and the glossary of terms was very much appreciated.&lt;br /&gt;
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==Group 4==&lt;br /&gt;
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===Subheading===&lt;br /&gt;
[[File:Chicken embryo E-cad and P-cad gastrulation.png|500px]]&lt;br /&gt;
&lt;br /&gt;
embryo&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/sites/gquery?term=embryo ''embryo'']&lt;br /&gt;
&lt;br /&gt;
notochord&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/pubmed?term=notochord ''notochord'']&lt;br /&gt;
&lt;br /&gt;
References&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;28786202&amp;lt;/pubmed&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_3&amp;diff=311270</id>
		<title>Talk:2017 Group Project 3</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_3&amp;diff=311270"/>
		<updated>2017-10-12T01:16:32Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Review */&lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
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&amp;lt;!-- Do not remove template above from the project discussion page --&amp;gt;&lt;br /&gt;
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==Suggested Starting Places==&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 3 below are some starting places.&lt;br /&gt;
&lt;br /&gt;
{{Heart Links}}&lt;br /&gt;
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PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Heart+Development ''Heart Development''] | [http://www.ncbi.nlm.nih.gov/pubmed?term=Cardiac+Development ''Cardiac Development'']&lt;br /&gt;
&lt;br /&gt;
BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Heart+Development ''Heart Development'']&lt;br /&gt;
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Recent papers&lt;br /&gt;
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&amp;lt;pubmed limit=5&amp;gt;Heart+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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==Group Topic Intro==&lt;br /&gt;
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=Peer Review=&lt;br /&gt;
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'''Peer review project 3:''' &lt;br /&gt;
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Some general comments to the project: &lt;br /&gt;
*The project contained both developmental origin, timeline, signalling processes, current research and findings, animals model and abnormal development sections. The project therefore has all the sections which were a requirement for the project. &lt;br /&gt;
* Overall, I think the project was good. It was well written, easy to understand as a student, the sections correlated well and the context was good. I especially liked the signalling section, even though some context is missing.   I think the idea of adding a treatment part to project is a good but I could not find it in the project. As mentioned some context is missing, which is the notch pathway, sonic hedgehog and retinoic acid sections. &lt;br /&gt;
* The project has a good introduction. You have a clear idea of what you are about to read, which is nice. &lt;br /&gt;
* The layout could be a lot better, I think the picture location could be adjusted. In the developmental origin part, the pictures make the section look very confusing. Some of the subheadings, like the abnormal development is pushed to side by the pictures, so when you scroll down the project you miss it. &lt;br /&gt;
* In general, the pictures miss their caption, sources and number.  Therefore, you do not know which picture there is referred to when you are reading the project. I miss some more pictures in the developmental sections. Some of the home made drawing is not very descriptive  &lt;br /&gt;
* In the developmental origin section I think the last sentence is very long. You get so much information in one sentence that you sometimes forget what you just read. &lt;br /&gt;
* The timeline is easy to read and understand. Could contain some key discoveries.   &lt;br /&gt;
* Thought the glossary of terms is a nice addition to the project. &lt;br /&gt;
* Overall the referencing is good, but in some sections like primary heart field and heart tube formation, the referencing is missing. In some sections the articles/or links are at the bottom of the section, which makes it a little confusing. &lt;br /&gt;
* I don’t feel like the primary heart field and heart tube formation correlates very well with the secondary heart field and cardiac looping section. When I start reading the latter I feel like I am starting on something completely new instead of continuing reading on the heart developing. I get the feeling I am reading two different persons work, and some work should be put into these sections to make it feel more fluent. &lt;br /&gt;
* An idea for your project could be that you add a short anatomy section after the introduction, so the reader gets a picture and an overview of how the heart is structured. Then it is easier to understand the developing of the heart when you know how the heart is going to end up looking like. &lt;br /&gt;
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Don’t forget to remove the hyperlinks that are under ‘Heart’ at the beginning of the page. Remove student numbers from the page. Add a brief description under images so that readers will understand what the image is showing. Remember to move references that are written in some sections to the ‘References’ subheading. The Notch Pathway is incomplete. &lt;br /&gt;
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Subheadings and content that have been used show a good understanding of the topic area. The use of a table for the ‘Development Timeline’ shows the teams innovativeness. The use of simple sentences in the table allows readers to understand content simply. References have been done well, they are cited properly. The team have used their own images to show their understanding of the heart. The images that they have used have been properly cited: there are references, copyright statements and the Student Image template. Thorough description of abnormal development, animal models and current research which shows the comprehensive research that was done for the heart. The use of Glossary of Terms is helpful to readers who may not understand what some terms are. &lt;br /&gt;
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Very informative and well written wiki. The glossary of terms is particularly useful and presented beautifully. The frequent addition of images and hand-made drawings are really good as they provide a useful visual reference point. The inclusion of a brief overview about the different animals studied in regards to the heart is very interesting. There is a minor spelling error in the table referring to Developmental timeline (week 5). The use of references is great, however maybe just include the links at the bottom of the wiki, to assist with the flow of information. Also add a description of your images so that viewers can more easily identify how the image relates to the text and the relevance of it. Overall, a really good wiki and well done.&lt;br /&gt;
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The project is very good. There is a lot information on the page, there is a good description of each picture when you click on them, and there is a good brief introduction of each topic before going into depth on certain points. Most things are described clearly with pictures to support the information. Ending the project with a glossary of terms adds clarity to the project. &lt;br /&gt;
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In particular, the “Developmental Signalling Processes” section is excellent. There is a description of where molecules are expressed, what cells they act on, the molecules’ roles in the cell signalling pathway on individual cells, and the molecules’ roles in overall heart development. The table describing different types of FGF signalling is excellent. In this section and throughout the project, there is a lot of description of research that has led to the discovery of the information presented on this page. The section “Animal Models” and “Current Research and Findings” add to this. &lt;br /&gt;
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There are still a couple things to be fixed before the project is complete. There are some grammatical and spelling errors, particularly in “Proepicardium and Coronary Heart Development” that need to be edited. Some subheadings have nothing under them. Some references need to be fixed. Copyright information is needed when you click on some of the pictures. Instead of just using a paragraph style, emphasizing information by bolding specific words or using bulleted information may make the project easier to read and understand. Near the beginning of the project, a picture of the locations of the truncus arteriosus, bulbus cordis, primitive ventricle, and primitive atrium in the heart tube may add to the description of early development. In addition, a description of valve development could add to the project. Overall very good project. &lt;br /&gt;
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Use of headings and subheadings break this complex developmental process in to understandable, clear sections. &lt;br /&gt;
The images chosen to reinforce the material are appropriate and I particularly like that time has been taken to draw a number of these.    &lt;br /&gt;
There does seem to be an awful lot of information, and I wonder if this can be cut down at all. For example there is the section on signaling during development, which is a more complex section to understand. This is greatly helped by the diagrams but I can see that there are additional headings that are yet to have information added. It might be an idea to pick a few signaling pathways that occur and really perfect those. I think it has the potential to become very confusing to the reader otherwise. &lt;br /&gt;
It is very useful to the reader that you have included a glossary of terms, however I wonder if it may be more effective if this table is placed at the beginning of the page, or as a link at the top that can be opened up, so as the reader can familirise themselves with the terms prior to reading the page. &lt;br /&gt;
The page appears to be referenced extensively throughout and appropriately. Good job &lt;br /&gt;
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Overall, this page has a good structure and was enjoyable to read. The headings and subheadings were clear and made it easier to understand the development process of the Heart. Perhaps it would be better to include relevant background information of the heart before jumping into the developmental process straightaway. There is a good amount of images (and well-drawn images) accompanying the text which aided in understanding the content, however some were not labelled with their appropriate descriptions. Most parts were cited correctly and properly, however some areas weren't cited at all such as &amp;quot;Current Research and Findings and &amp;quot;Cardiac Stem Cells&amp;quot;. Also, some references were not done properly, check the &amp;quot;Primary Heart Field and Heart Tube Formation&amp;quot; section. Some sections were left blank, however I assume they will be completed over time. Glossary of terms was clever and made the content easier to understand (the heart is quite complicated to understand). Well done overall.&lt;br /&gt;
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Overall, this page had a finished feel because the page is so heavily packed with information, there are some sections that were not completed. There is however, a lot of information that may leave the reader feeling a bit overwhelmed. Some sections are also hard to understand and comprehend especially due to the heavy use of biotechnological jargon (ie. SMAD-dependent, SMAD-independent pathways, β-catenin). A terminology/glossary section would be extremely helpful for this issue. I'd advise using more images in &amp;quot;Abnormal Development&amp;quot; (ie. x-rays or physical observations of sufferers) to help the reader visualise such abnormalities. Referencing under images should be moved to the references section and should be referenced using the '''''&amp;lt; ref &amp;gt;'''  '''&amp;lt; / ref &amp;gt;''''' if in text. Overall, there is a lot of information, some of which is not necessarily important. I'd advise to cut down, make paragraphs more simple and straight to the point, and use images to help the reader visually understand and comprehend.&lt;br /&gt;
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Introduction is very good and explains a lot. Under the heading “Primary heart field and heart tube formation” – the reference at the bottom should be removed.&lt;br /&gt;
Secondary heart field and cardiac looping: First sentence doesn’t really make sense, maybe switch it up a bit. &lt;br /&gt;
Under current research and findings you have labelled a figure figure 1, when it is not the first figure in your wiki page, seems a little confusing. Images also don’t have appriopriate copyright info, description and referencing. Also figure 2 is placed right in the middle of the sentence, maybe put it to the right so it doesn’t interrupt reading. &lt;br /&gt;
Information could be formatted better under the heading atrial septal defect! Maybe some subheadings for the different defects? Same goes with the ventricular septal defect, its easier to read when things are broken up. Glossary is very good!&lt;br /&gt;
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All the information written on your page is very well written and easily understood. &lt;br /&gt;
Images could be labelled better, add a figure to each of them as when you are referring to figure 1 and 2 in your writing, the images aren’t labelled so its hard to tell what image you are referring to. &lt;br /&gt;
With references, I don’t like how there is a bunch at the end of some headings? Could be because you still need to read them but looks messy. &lt;br /&gt;
There is an overwhelming amount of information, so good job on doing so much research but it was quite tedious to read, not sure if this much information is needed? But it is very hard to fault your wiki page so this might be a bit picky.&lt;br /&gt;
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The introduction is a brief and clear overview of the page. I liked how you acknowledged what your page will explore about the heart development. The “Developmental origin” subheading had good information and good diagrams in addition. However, I would adjust your layout a bit in this section so that the diagrams don’t look so awkward. You could do this by breaking down that second paragraph. The timeline provided a brief overview but I would also suggest adding another column for images. There is also a spelling error on week 5 – it says “srtats” where it should be “starts”.&lt;br /&gt;
As you go into “primary heart field and heart tube formation”, “secondary heart field and cardiac looping” and the next few sections, the references appear at the bottom of the sections. You should fix this so that they only appear in the reference list at the end. You could also probably bold “heart tube fusion”, “heart looping” and other terms in your developmental timeline since you explore them in depth.&lt;br /&gt;
The “developmental signalling process” subheading is very detailed. Since you also have a few more parts to complete into this section, it might be better to try to minimise some of the text. Your inclusion of current research is good and unique as you explore one paper in depth. However, I would suggest that you find another one or two. The “animal models” subheading should probably have a diagram or two of the referenced research papers if possible. Again with “abnormal development” subheading I would suggest some more images to see what these defects look like and possibly cutting down some text. In “future questions” you might also be able to provide a possible direction research might take to potentially answer this question. Also, you had a very good, long list of references.&lt;br /&gt;
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The page goes through everything required for the project page. It would be nice if the pictures on the page have a figure number and a short title on the figures, so it is easier for the reader to understand what figure belongs to what part of the section. A figure number on the picture makes it able for the writer to refer to a specific picture. There is a good use of tables and self-drawn figures/picture. This makes the page clearer and more readable. There are some references on the page that needs a different formatting, so it is not fully viewed in the sections. It is important that the references are given right after the specific section and not at the bottom of the section. &lt;br /&gt;
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*'''The Introduction''' section gives a good excitement for the reader before reading the page. This gives an idea of what information to expect from the page. A little section about the anatomy of the heart and a picture could give a better preparation for the reader to understand the developmental part of the heart. &lt;br /&gt;
*'''The Development Origin''' section has a bit confusing layout. &lt;br /&gt;
*I like that the '''Cardiac Neural Crest and Outflow tract''' sections have a self-drawn picture, but maybe you can draw it a bit clearer, so it is easier to read the writing and understand the figure  There is no figure text on the page of the figure.&lt;br /&gt;
*'''Current Research And Findings, Animal Models and Abnormal Development:''' These sections have a bit of a messy layout. The context is good, but there I a lot of text and pictures kind of mingling into each other. You could make these sections more separate in the layout. &lt;br /&gt;
*'''The Glossary of terms''' helps the reader a lot.&lt;br /&gt;
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The headings were all neat, concise and impressive. It successfully highlighted and sectioned the key topics in the development of the heart. The addition of the technical signalling pathways and the details of the development were well summarised with appropriate references in superscript format. There was a nice variety of visual resources, both hand drawn and externally sourced. Most images have their copyright approval and reference included perfectly, except &amp;quot;Figure 1 Morphological defects in CTCF mutant embryonic hearts&amp;quot; and &amp;quot;Figure 2 - defects of mitochondria in CTCF mutant hearts&amp;quot;. There was a nice flow throughout the page through the use of effective paragraph sectioning. The table for the glossary of terms was really useful and neat.&lt;br /&gt;
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Some of the images didn't have a box around it and these figures were not labelled, this should be easily changed in the edit mode. Some of the hand drawn images were somewhat unclear, due to the writing as well as the rough outline of the heart. Signatures should also be removed. The references were also retained in the bottom of the sections. It was a confusing because it wasn't next to any paragraphs that needed to be referenced. A reference was also repeated in this section. &lt;br /&gt;
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''For example:''&lt;br /&gt;
&amp;quot;This image is based upon Robert H Anderson, Sandra Webb, Nigel A Brown, Wouter Lamers, Antoon Moorman Development of the heart: (3) formation of the ventricular outflow tracts, arterial valves, and intrapericardial arterial trunks. Heart: 2003, 89(9);1110-8 PubMed 12923046&lt;br /&gt;
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Robert H Anderson, Sandra Webb, Nigel A Brown, Wouter Lamers, Antoon Moorman Development of the heart: (3) formation of the ventricular outflow tracts, arterial valves, and intrapericardial arterial trunks. Heart: 2003, 89(9);1110-8 PubMed 12923046&lt;br /&gt;
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Marc Sylva, Maurice J B van den Hoff, Antoon F M Moorman Development of the human heart. Am. J. Med. Genet. A: 2014, 164A(6);1347-71 PubMed 23633400&amp;quot;&lt;br /&gt;
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Finally, there is a great variety of reputable sources of information. The only thing that needs changing is that the reference list should be revised. Some were left as a link and the list were inconsistent with its reference format.&lt;br /&gt;
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This wikipage had all the sections required for this assignment and the team was very detailed in their content. There was also a good amount of referencing. However for certain areas, the entire reference was there instead of just the number. Also, the student numbers should be removed from the page. There was also a good number of photos used and it was good that they had a mix between self-drawn images and images obtained online. However, a way that could improve the images would be to add a description or a caption under each figure so it's easier to know what the picture is about. Some photos in this article lacked description, reference and copyright information, so that could be added as well. For most of the article, I can see that the team carried out a great amount of research for this topic, however it was a little difficult to understand some parts as they were very lengthy and slightly too content heavy. For the developmental timeline, the use of a table was good but the information could be presented in a more concise manner and the headings could be slightly more prominent to make it more readable. The signalling processes was also very well researched but quite lengthy, perhaps a few main signalling pathways could be chosen instead. For the abnormal developments, each abnormalities were well researched on. Perhaps images could be added to show the abnormalities and also maybe one or two more defects would be good. Overall, I think this group did a great job in researching and providing information on this wikipage. Maybe with a bit of tweaking here and there to make it more concise and readable, this wikipage would make a really good project.&lt;br /&gt;
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Well-structured page which seems to be quite detailed and long to read. The extensive use of subheadings make it a little harder to follow in some areas such as under “Developmental timeline”, where after the table the subheading “Primary Heart Field and…” appears to be a little misplaced or is lacking flow completely. Need to remove the student numbers from the page and also the two links under the initial “Heart” heading. In text referencing throughout the page seems to be consistent for the most part however, there are some areas where the correct format needs to be used (i.e., under “Wnt signaling” and “Cardiac Neural Crest and Outflow tract”). Some images do have a description of what is addressed however, many of them do not – this expansion would help with the overall reading experience as well as add further information for understanding. Overall, an extensive knowledge of the topic is well demonstrated through an attention to detail – but perhaps a more concise approach would add some clarity to the text. &lt;br /&gt;
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The introduction was very good! I like how it introduced why the heart is so critical in early development, explained what you were going to discuss and where there would be gaps due to a lack of medical knowledge. The information in developmental origin and the developmental timeline is really great, however, I think you need to consider joining these two headings and not splitting them into one. You also state in developmental origin &amp;quot;as seen in figure two&amp;quot;, however, none of your images have figure titles so I am not sure which figure you're actually referring to. The timeline is a good basic reference point, so I think it would be nice for it to be before the origin outline as it gives the basics which you then go into more detail about. I like that you put in the developmental signalling processes and then outlined each one of these, obviously the rest of those processes that have subheadings but no information just need to be finished. The current research is really interesting, again images just need a figure of some sort. The future questions section is a little confusing as I'm not sure if that's an area you're going to go into more depth over or if that's a future question you think research should look in to? So a clarification would be good. The glossary of terms is super helpful and all referencing looks good!&lt;br /&gt;
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At first glance this project seems very detailed and lengthy. In my opinion, it could have too much text and maybe summarizing and condensing some sections could be beneficial. Collapsible windows or maybe more use of subheadings or dot points could be used to make the page clearer and less overwhelming. The diagrams and tables are very engaging and informative.  However I do think the position and sizing of the diagrams could be improved to align it with the text better. The text and most of the diagrams seem to be well referenced. Another suggestion for this page would be to make the overall title of ‘Heart’ larger and clearer, perhaps include a diagram of the heart with the title to make it more attractive. The overall title should also be placed above the contents section.      &lt;br /&gt;
Despite these suggestions, well done this page is very detailed and informative and you have clearly put a lot of work and effort into it.&lt;br /&gt;
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Great detailing of the development and signaling processes involved, it really showed me that the group had extensive knowledge on this topic.  In addition, there is a good balance of personal images (e.g. wnt signaling diagram) and web images which showed me that the group dedicated time to make sure the reader fully understood each aspect of the topic.  Most images also are properly cited with copyright statements, references, and description (some are missing, but overall are done well).  It was very helpful to include a glossary of terms at the end for the reader to refer to. An image for the cardiac looping steps would help to visualize steps. Information needs to be added for the notch pathway, sonic hedgehog, retinoic acid.  While the detail is very informative, there is a lot of information and can be a little overwhelming.  It might help to add more bullet points (with only essential information) or to edit some of the superfluous information. In addition, captions for the images would help so that the reader knows which image you’re referring to when referring to them in the text.&lt;br /&gt;
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'Introduction' is clear and informative, well referenced and gives a good outline for the rest of the page. 'Developmental Origin' has a bit of a confusing set up.. pictures are seemingly scattered and need captions. The 'Morphology of the Heart tube formation' hand-drawn figure is almost an exact replica of the original.. not sure if this is allowed because they are so similar. 'Developmental Timeline' has a very brief table.. would benefit from a better description of each week of development. This section has a couple of random references that should be at the bottom. 'Developmental Signalling Processes' diagrams need captions. There is a lot of information here which is very detailed. 'Current Research and Findings' has good subheadings and picture use; pictures need to have copyright information and citations added. Very detailed with good references throughought. 'Future Questions' needs to be added to but has shown evidence of initial research into this area. 'Glossary of terms' is a very good idea that has not yet been shown in other group topics. Maybe look into researching how to link certain words in the article to redirect to the bottom of the page to the Glossary of terms for quick definitions? Some references also need to be properly cited in the 'References' section. Over all, really well researched with some sections needing a bit more work.&lt;br /&gt;
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Overall a very in-depth page with most of the required subjects covered. Some general notes; the figures would have benefited from appropriate captions but were helpful nonetheless. Referencing and overall visual formatting could be improved. The page is written well and enjoyable to read. &lt;br /&gt;
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&amp;quot;Primary heart field and heart tube formation&amp;quot; could benefit from a diagram or figure since it is a lot of text that could be hard to conceptualise. The signalling processes are explained very well and in deep detail. Just a note though; the addressing of so many different variables in the signalling is a little confusing and hard to follow. Perhaps a more condensed response might be a little more straightforward. The diagram of the signalling pathways under &amp;quot;Wnt Signalling&amp;quot; was likewise hard to follow, and no key was given. Current Research and Animal Models were covered well and the explanation for their research and the key results highlighted were fascinating. Abnormal development was likewise addressed very well and the glossary of terms was very much appreciated. &lt;br /&gt;
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		<author><name>Z5113034</name></author>
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	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_3&amp;diff=311268</id>
		<title>Talk:2017 Group Project 3</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_3&amp;diff=311268"/>
		<updated>2017-10-12T01:16:11Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Review */&lt;/p&gt;
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==Suggested Starting Places==&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 3 below are some starting places.&lt;br /&gt;
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{{Heart Links}}&lt;br /&gt;
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PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Heart+Development ''Heart Development''] | [http://www.ncbi.nlm.nih.gov/pubmed?term=Cardiac+Development ''Cardiac Development'']&lt;br /&gt;
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BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Heart+Development ''Heart Development'']&lt;br /&gt;
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Recent papers&lt;br /&gt;
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&amp;lt;pubmed limit=5&amp;gt;Heart+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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==Group Topic Intro==&lt;br /&gt;
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=Peer Review=&lt;br /&gt;
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'''Peer review project 3:''' &lt;br /&gt;
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Some general comments to the project: &lt;br /&gt;
*The project contained both developmental origin, timeline, signalling processes, current research and findings, animals model and abnormal development sections. The project therefore has all the sections which were a requirement for the project. &lt;br /&gt;
* Overall, I think the project was good. It was well written, easy to understand as a student, the sections correlated well and the context was good. I especially liked the signalling section, even though some context is missing.   I think the idea of adding a treatment part to project is a good but I could not find it in the project. As mentioned some context is missing, which is the notch pathway, sonic hedgehog and retinoic acid sections. &lt;br /&gt;
* The project has a good introduction. You have a clear idea of what you are about to read, which is nice. &lt;br /&gt;
* The layout could be a lot better, I think the picture location could be adjusted. In the developmental origin part, the pictures make the section look very confusing. Some of the subheadings, like the abnormal development is pushed to side by the pictures, so when you scroll down the project you miss it. &lt;br /&gt;
* In general, the pictures miss their caption, sources and number.  Therefore, you do not know which picture there is referred to when you are reading the project. I miss some more pictures in the developmental sections. Some of the home made drawing is not very descriptive  &lt;br /&gt;
* In the developmental origin section I think the last sentence is very long. You get so much information in one sentence that you sometimes forget what you just read. &lt;br /&gt;
* The timeline is easy to read and understand. Could contain some key discoveries.   &lt;br /&gt;
* Thought the glossary of terms is a nice addition to the project. &lt;br /&gt;
* Overall the referencing is good, but in some sections like primary heart field and heart tube formation, the referencing is missing. In some sections the articles/or links are at the bottom of the section, which makes it a little confusing. &lt;br /&gt;
* I don’t feel like the primary heart field and heart tube formation correlates very well with the secondary heart field and cardiac looping section. When I start reading the latter I feel like I am starting on something completely new instead of continuing reading on the heart developing. I get the feeling I am reading two different persons work, and some work should be put into these sections to make it feel more fluent. &lt;br /&gt;
* An idea for your project could be that you add a short anatomy section after the introduction, so the reader gets a picture and an overview of how the heart is structured. Then it is easier to understand the developing of the heart when you know how the heart is going to end up looking like. &lt;br /&gt;
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Don’t forget to remove the hyperlinks that are under ‘Heart’ at the beginning of the page. Remove student numbers from the page. Add a brief description under images so that readers will understand what the image is showing. Remember to move references that are written in some sections to the ‘References’ subheading. The Notch Pathway is incomplete. &lt;br /&gt;
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Subheadings and content that have been used show a good understanding of the topic area. The use of a table for the ‘Development Timeline’ shows the teams innovativeness. The use of simple sentences in the table allows readers to understand content simply. References have been done well, they are cited properly. The team have used their own images to show their understanding of the heart. The images that they have used have been properly cited: there are references, copyright statements and the Student Image template. Thorough description of abnormal development, animal models and current research which shows the comprehensive research that was done for the heart. The use of Glossary of Terms is helpful to readers who may not understand what some terms are. &lt;br /&gt;
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Very informative and well written wiki. The glossary of terms is particularly useful and presented beautifully. The frequent addition of images and hand-made drawings are really good as they provide a useful visual reference point. The inclusion of a brief overview about the different animals studied in regards to the heart is very interesting. There is a minor spelling error in the table referring to Developmental timeline (week 5). The use of references is great, however maybe just include the links at the bottom of the wiki, to assist with the flow of information. Also add a description of your images so that viewers can more easily identify how the image relates to the text and the relevance of it. Overall, a really good wiki and well done.&lt;br /&gt;
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The project is very good. There is a lot information on the page, there is a good description of each picture when you click on them, and there is a good brief introduction of each topic before going into depth on certain points. Most things are described clearly with pictures to support the information. Ending the project with a glossary of terms adds clarity to the project. &lt;br /&gt;
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In particular, the “Developmental Signalling Processes” section is excellent. There is a description of where molecules are expressed, what cells they act on, the molecules’ roles in the cell signalling pathway on individual cells, and the molecules’ roles in overall heart development. The table describing different types of FGF signalling is excellent. In this section and throughout the project, there is a lot of description of research that has led to the discovery of the information presented on this page. The section “Animal Models” and “Current Research and Findings” add to this. &lt;br /&gt;
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There are still a couple things to be fixed before the project is complete. There are some grammatical and spelling errors, particularly in “Proepicardium and Coronary Heart Development” that need to be edited. Some subheadings have nothing under them. Some references need to be fixed. Copyright information is needed when you click on some of the pictures. Instead of just using a paragraph style, emphasizing information by bolding specific words or using bulleted information may make the project easier to read and understand. Near the beginning of the project, a picture of the locations of the truncus arteriosus, bulbus cordis, primitive ventricle, and primitive atrium in the heart tube may add to the description of early development. In addition, a description of valve development could add to the project. Overall very good project. &lt;br /&gt;
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Use of headings and subheadings break this complex developmental process in to understandable, clear sections. &lt;br /&gt;
The images chosen to reinforce the material are appropriate and I particularly like that time has been taken to draw a number of these.    &lt;br /&gt;
There does seem to be an awful lot of information, and I wonder if this can be cut down at all. For example there is the section on signaling during development, which is a more complex section to understand. This is greatly helped by the diagrams but I can see that there are additional headings that are yet to have information added. It might be an idea to pick a few signaling pathways that occur and really perfect those. I think it has the potential to become very confusing to the reader otherwise. &lt;br /&gt;
It is very useful to the reader that you have included a glossary of terms, however I wonder if it may be more effective if this table is placed at the beginning of the page, or as a link at the top that can be opened up, so as the reader can familirise themselves with the terms prior to reading the page. &lt;br /&gt;
The page appears to be referenced extensively throughout and appropriately. Good job &lt;br /&gt;
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Overall, this page has a good structure and was enjoyable to read. The headings and subheadings were clear and made it easier to understand the development process of the Heart. Perhaps it would be better to include relevant background information of the heart before jumping into the developmental process straightaway. There is a good amount of images (and well-drawn images) accompanying the text which aided in understanding the content, however some were not labelled with their appropriate descriptions. Most parts were cited correctly and properly, however some areas weren't cited at all such as &amp;quot;Current Research and Findings and &amp;quot;Cardiac Stem Cells&amp;quot;. Also, some references were not done properly, check the &amp;quot;Primary Heart Field and Heart Tube Formation&amp;quot; section. Some sections were left blank, however I assume they will be completed over time. Glossary of terms was clever and made the content easier to understand (the heart is quite complicated to understand). Well done overall.&lt;br /&gt;
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Overall, this page had a finished feel because the page is so heavily packed with information, there are some sections that were not completed. There is however, a lot of information that may leave the reader feeling a bit overwhelmed. Some sections are also hard to understand and comprehend especially due to the heavy use of biotechnological jargon (ie. SMAD-dependent, SMAD-independent pathways, β-catenin). A terminology/glossary section would be extremely helpful for this issue. I'd advise using more images in &amp;quot;Abnormal Development&amp;quot; (ie. x-rays or physical observations of sufferers) to help the reader visualise such abnormalities. Referencing under images should be moved to the references section and should be referenced using the '''''&amp;lt; ref &amp;gt;'''  '''&amp;lt; / ref &amp;gt;''''' if in text. Overall, there is a lot of information, some of which is not necessarily important. I'd advise to cut down, make paragraphs more simple and straight to the point, and use images to help the reader visually understand and comprehend.&lt;br /&gt;
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Introduction is very good and explains a lot. Under the heading “Primary heart field and heart tube formation” – the reference at the bottom should be removed.&lt;br /&gt;
Secondary heart field and cardiac looping: First sentence doesn’t really make sense, maybe switch it up a bit. &lt;br /&gt;
Under current research and findings you have labelled a figure figure 1, when it is not the first figure in your wiki page, seems a little confusing. Images also don’t have appriopriate copyright info, description and referencing. Also figure 2 is placed right in the middle of the sentence, maybe put it to the right so it doesn’t interrupt reading. &lt;br /&gt;
Information could be formatted better under the heading atrial septal defect! Maybe some subheadings for the different defects? Same goes with the ventricular septal defect, its easier to read when things are broken up. Glossary is very good!&lt;br /&gt;
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All the information written on your page is very well written and easily understood. &lt;br /&gt;
Images could be labelled better, add a figure to each of them as when you are referring to figure 1 and 2 in your writing, the images aren’t labelled so its hard to tell what image you are referring to. &lt;br /&gt;
With references, I don’t like how there is a bunch at the end of some headings? Could be because you still need to read them but looks messy. &lt;br /&gt;
There is an overwhelming amount of information, so good job on doing so much research but it was quite tedious to read, not sure if this much information is needed? But it is very hard to fault your wiki page so this might be a bit picky.&lt;br /&gt;
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The introduction is a brief and clear overview of the page. I liked how you acknowledged what your page will explore about the heart development. The “Developmental origin” subheading had good information and good diagrams in addition. However, I would adjust your layout a bit in this section so that the diagrams don’t look so awkward. You could do this by breaking down that second paragraph. The timeline provided a brief overview but I would also suggest adding another column for images. There is also a spelling error on week 5 – it says “srtats” where it should be “starts”.&lt;br /&gt;
As you go into “primary heart field and heart tube formation”, “secondary heart field and cardiac looping” and the next few sections, the references appear at the bottom of the sections. You should fix this so that they only appear in the reference list at the end. You could also probably bold “heart tube fusion”, “heart looping” and other terms in your developmental timeline since you explore them in depth.&lt;br /&gt;
The “developmental signalling process” subheading is very detailed. Since you also have a few more parts to complete into this section, it might be better to try to minimise some of the text. Your inclusion of current research is good and unique as you explore one paper in depth. However, I would suggest that you find another one or two. The “animal models” subheading should probably have a diagram or two of the referenced research papers if possible. Again with “abnormal development” subheading I would suggest some more images to see what these defects look like and possibly cutting down some text. In “future questions” you might also be able to provide a possible direction research might take to potentially answer this question. Also, you had a very good, long list of references.&lt;br /&gt;
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The page goes through everything required for the project page. It would be nice if the pictures on the page have a figure number and a short title on the figures, so it is easier for the reader to understand what figure belongs to what part of the section. A figure number on the picture makes it able for the writer to refer to a specific picture. There is a good use of tables and self-drawn figures/picture. This makes the page clearer and more readable. There are some references on the page that needs a different formatting, so it is not fully viewed in the sections. It is important that the references are given right after the specific section and not at the bottom of the section. &lt;br /&gt;
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*'''The Introduction''' section gives a good excitement for the reader before reading the page. This gives an idea of what information to expect from the page. A little section about the anatomy of the heart and a picture could give a better preparation for the reader to understand the developmental part of the heart. &lt;br /&gt;
*'''The Development Origin''' section has a bit confusing layout. &lt;br /&gt;
*I like that the '''Cardiac Neural Crest and Outflow tract''' sections have a self-drawn picture, but maybe you can draw it a bit clearer, so it is easier to read the writing and understand the figure  There is no figure text on the page of the figure.&lt;br /&gt;
*'''Current Research And Findings, Animal Models and Abnormal Development:''' These sections have a bit of a messy layout. The context is good, but there I a lot of text and pictures kind of mingling into each other. You could make these sections more separate in the layout. &lt;br /&gt;
*'''The Glossary of terms''' helps the reader a lot.&lt;br /&gt;
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The headings were all neat, concise and impressive. It successfully highlighted and sectioned the key topics in the development of the heart. The addition of the technical signalling pathways and the details of the development were well summarised with appropriate references in superscript format. There was a nice variety of visual resources, both hand drawn and externally sourced. Most images have their copyright approval and reference included perfectly, except &amp;quot;Figure 1 Morphological defects in CTCF mutant embryonic hearts&amp;quot; and &amp;quot;Figure 2 - defects of mitochondria in CTCF mutant hearts&amp;quot;. There was a nice flow throughout the page through the use of effective paragraph sectioning. The table for the glossary of terms was really useful and neat.&lt;br /&gt;
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Some of the images didn't have a box around it and these figures were not labelled, this should be easily changed in the edit mode. Some of the hand drawn images were somewhat unclear, due to the writing as well as the rough outline of the heart. Signatures should also be removed. The references were also retained in the bottom of the sections. It was a confusing because it wasn't next to any paragraphs that needed to be referenced. A reference was also repeated in this section. &lt;br /&gt;
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''For example:''&lt;br /&gt;
&amp;quot;This image is based upon Robert H Anderson, Sandra Webb, Nigel A Brown, Wouter Lamers, Antoon Moorman Development of the heart: (3) formation of the ventricular outflow tracts, arterial valves, and intrapericardial arterial trunks. Heart: 2003, 89(9);1110-8 PubMed 12923046&lt;br /&gt;
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Robert H Anderson, Sandra Webb, Nigel A Brown, Wouter Lamers, Antoon Moorman Development of the heart: (3) formation of the ventricular outflow tracts, arterial valves, and intrapericardial arterial trunks. Heart: 2003, 89(9);1110-8 PubMed 12923046&lt;br /&gt;
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Marc Sylva, Maurice J B van den Hoff, Antoon F M Moorman Development of the human heart. Am. J. Med. Genet. A: 2014, 164A(6);1347-71 PubMed 23633400&amp;quot;&lt;br /&gt;
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Finally, there is a great variety of reputable sources of information. The only thing that needs changing is that the reference list should be revised. Some were left as a link and the list were inconsistent with its reference format.&lt;br /&gt;
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This wikipage had all the sections required for this assignment and the team was very detailed in their content. There was also a good amount of referencing. However for certain areas, the entire reference was there instead of just the number. Also, the student numbers should be removed from the page. There was also a good number of photos used and it was good that they had a mix between self-drawn images and images obtained online. However, a way that could improve the images would be to add a description or a caption under each figure so it's easier to know what the picture is about. Some photos in this article lacked description, reference and copyright information, so that could be added as well. For most of the article, I can see that the team carried out a great amount of research for this topic, however it was a little difficult to understand some parts as they were very lengthy and slightly too content heavy. For the developmental timeline, the use of a table was good but the information could be presented in a more concise manner and the headings could be slightly more prominent to make it more readable. The signalling processes was also very well researched but quite lengthy, perhaps a few main signalling pathways could be chosen instead. For the abnormal developments, each abnormalities were well researched on. Perhaps images could be added to show the abnormalities and also maybe one or two more defects would be good. Overall, I think this group did a great job in researching and providing information on this wikipage. Maybe with a bit of tweaking here and there to make it more concise and readable, this wikipage would make a really good project.&lt;br /&gt;
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Well-structured page which seems to be quite detailed and long to read. The extensive use of subheadings make it a little harder to follow in some areas such as under “Developmental timeline”, where after the table the subheading “Primary Heart Field and…” appears to be a little misplaced or is lacking flow completely. Need to remove the student numbers from the page and also the two links under the initial “Heart” heading. In text referencing throughout the page seems to be consistent for the most part however, there are some areas where the correct format needs to be used (i.e., under “Wnt signaling” and “Cardiac Neural Crest and Outflow tract”). Some images do have a description of what is addressed however, many of them do not – this expansion would help with the overall reading experience as well as add further information for understanding. Overall, an extensive knowledge of the topic is well demonstrated through an attention to detail – but perhaps a more concise approach would add some clarity to the text. &lt;br /&gt;
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The introduction was very good! I like how it introduced why the heart is so critical in early development, explained what you were going to discuss and where there would be gaps due to a lack of medical knowledge. The information in developmental origin and the developmental timeline is really great, however, I think you need to consider joining these two headings and not splitting them into one. You also state in developmental origin &amp;quot;as seen in figure two&amp;quot;, however, none of your images have figure titles so I am not sure which figure you're actually referring to. The timeline is a good basic reference point, so I think it would be nice for it to be before the origin outline as it gives the basics which you then go into more detail about. I like that you put in the developmental signalling processes and then outlined each one of these, obviously the rest of those processes that have subheadings but no information just need to be finished. The current research is really interesting, again images just need a figure of some sort. The future questions section is a little confusing as I'm not sure if that's an area you're going to go into more depth over or if that's a future question you think research should look in to? So a clarification would be good. The glossary of terms is super helpful and all referencing looks good!&lt;br /&gt;
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At first glance this project seems very detailed and lengthy. In my opinion, it could have too much text and maybe summarizing and condensing some sections could be beneficial. Collapsible windows or maybe more use of subheadings or dot points could be used to make the page clearer and less overwhelming. The diagrams and tables are very engaging and informative.  However I do think the position and sizing of the diagrams could be improved to align it with the text better. The text and most of the diagrams seem to be well referenced. Another suggestion for this page would be to make the overall title of ‘Heart’ larger and clearer, perhaps include a diagram of the heart with the title to make it more attractive. The overall title should also be placed above the contents section.      &lt;br /&gt;
Despite these suggestions, well done this page is very detailed and informative and you have clearly put a lot of work and effort into it.&lt;br /&gt;
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Great detailing of the development and signaling processes involved, it really showed me that the group had extensive knowledge on this topic.  In addition, there is a good balance of personal images (e.g. wnt signaling diagram) and web images which showed me that the group dedicated time to make sure the reader fully understood each aspect of the topic.  Most images also are properly cited with copyright statements, references, and description (some are missing, but overall are done well).  It was very helpful to include a glossary of terms at the end for the reader to refer to. An image for the cardiac looping steps would help to visualize steps. Information needs to be added for the notch pathway, sonic hedgehog, retinoic acid.  While the detail is very informative, there is a lot of information and can be a little overwhelming.  It might help to add more bullet points (with only essential information) or to edit some of the superfluous information. In addition, captions for the images would help so that the reader knows which image you’re referring to when referring to them in the text.&lt;br /&gt;
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'Introduction' is clear and informative, well referenced and gives a good outline for the rest of the page. 'Developmental Origin' has a bit of a confusing set up.. pictures are seemingly scattered and need captions. The 'Morphology of the Heart tube formation' hand-drawn figure is almost an exact replica of the original.. not sure if this is allowed because they are so similar. 'Developmental Timeline' has a very brief table.. would benefit from a better description of each week of development. This section has a couple of random references that should be at the bottom. 'Developmental Signalling Processes' diagrams need captions. There is a lot of information here which is very detailed. 'Current Research and Findings' has good subheadings and picture use; pictures need to have copyright information and citations added. Very detailed with good references throughought. 'Future Questions' needs to be added to but has shown evidence of initial research into this area. 'Glossary of terms' is a very good idea that has not yet been shown in other group topics. Maybe look into researching how to link certain words in the article to redirect to the bottom of the page to the Glossary of terms for quick definitions? Some references also need to be properly cited in the 'References' section. Over all, really well researched with some sections needing a bit more work.&lt;br /&gt;
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Overall a very in-depth page with most of the required subjects covered. Some general notes; the figures would have benefited from appropriate captions but were helpful nonetheless. Referencing and overall visual formatting could be improved. The page is written well and enjoyable to read. &lt;br /&gt;
&amp;quot;Primary heart field and heart tube formation&amp;quot; could benefit from a diagram or figure since it is a lot of text that could be hard to conceptualise. The signalling processes are explained very well and in deep detail. Just a note though; the addressing of so many different variables in the signalling is a little confusing and hard to follow. Perhaps a more condensed response might be a little more straightforward. The diagram of the signalling pathways under &amp;quot;Wnt Signalling&amp;quot; was likewise hard to follow, and no key was given. Current Research and Animal Models were covered well and the explanation for their research and the key results highlighted were fascinating. Abnormal development was likewise addressed very well and the glossary of terms was very much appreciated. &lt;br /&gt;
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		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311266</id>
		<title>User:Z5113034</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311266"/>
		<updated>2017-10-12T01:15:33Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Reviews */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341ProjectGroup2017table}}&lt;br /&gt;
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Here is the [[Student Page]] demonstration page I showed in the Practical class.&lt;br /&gt;
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Use this page to practice editing and don't forget to add a topic to the [[2017 Group Project 6]] page.&lt;br /&gt;
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[[Student Page]] [[Student Page]] [[Student Page]]&lt;br /&gt;
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The [https://docs.google.com/document/d/1Z0ui9HkyBsitcQuD5YYYp4JyTgSHmZFy6MoaOHyKAlI/edit group discussion]&lt;br /&gt;
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{{2017ANAT2341 footer}}&lt;br /&gt;
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===Subheading===&lt;br /&gt;
[[File:Chicken embryo E-cad and P-cad gastrulation.png|500px]]&lt;br /&gt;
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embryo&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/sites/gquery?term=embryo ''embryo'']&lt;br /&gt;
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notochord&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/pubmed?term=notochord ''notochord'']&lt;br /&gt;
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References&lt;br /&gt;
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&amp;lt;pubmed&amp;gt;28786202&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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=Peer Reviews=&lt;br /&gt;
==Group 1==&lt;br /&gt;
The most obvious flaw was the lack of polish in formatting of some of the page. Bullet points are only so useful when it comes to writing a wiki page, instead of taking notes. The page is unfinished, but, the content included especially in the &amp;quot;Development of Cerebral Cortex&amp;quot; and &amp;quot;Abnormalities associated with Cerebral Cortex Development&amp;quot; was extensive and well done. The large table that linked the development with the time period was very useful and the choice of bolding key words allowed the main idea in the paragraph to be quickly understood from a glance. The use of images very much enhanced the descriptions and checker-like the layout of the different abnormalities was refreshing. Some subheadings, such as the Anatomy and Function of the cerebral cortex, could be elaborated on but the overall structure of the page is logical and fluid, and the writing is clear and concise without being superficial.&lt;br /&gt;
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==Group 2==&lt;br /&gt;
The introduction is clear and well-thought-out; simple enough that the layman can understand but comprehensive enough to lead logically into the more extensive information on the page. Perhaps a discussion of the kidney's function ought to be included with the description of kidney structure. Kidney development; the choice of that particular style of formatting runs a risk of not tying the development with the timeline but the small table at the top serves well to stop that, even if it is a little of a hassle moving back and forth to keep up. The content was well-written and appropriate in voice and depth of knowledge. Visually well-presented with figures appropriately explained. Developmental abnormalities were covered well, and although bullet points may not be the best way to present the information, it allowed for the key points to be understood very quickly and effectively. The transition from topic to topic was logical and flowed appropriately. Some aspects of the page must of course be filled out but overall a well-rounded, well-structured and informative page. Well done.&lt;br /&gt;
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==Group 3==&lt;br /&gt;
Overall a very in-depth page with most of the required subjects covered. Some general notes; the figures would have benefited from appropriate captions but were helpful nonetheless. Referencing and overall visual formatting could be improved. The page is written well and enjoyable to read. &lt;br /&gt;
&amp;quot;Primary heart field and heart tube formation&amp;quot; could benefit from a diagram or figure since it is a lot of text that could be hard to conceptualise. The signalling processes are explained very well and in deep detail. Just a note though; the addressing of so many different variables in the signalling is a little confusing and hard to follow. Perhaps a more condensed response might be a little more straightforward. The diagram of the signalling pathways under &amp;quot;Wnt Signalling&amp;quot; was likewise hard to follow, and no key was given. Current Research and Animal Models were covered well and the explanation for their research and the key results highlighted were fascinating. Abnormal development was likewise addressed very well and the glossary of terms was very much appreciated.&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311226</id>
		<title>User:Z5113034</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311226"/>
		<updated>2017-10-11T23:30:46Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Reviews */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341ProjectGroup2017table}}&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Here is the [[Student Page]] demonstration page I showed in the Practical class.&lt;br /&gt;
&lt;br /&gt;
Use this page to practice editing and don't forget to add a topic to the [[2017 Group Project 6]] page.&lt;br /&gt;
&lt;br /&gt;
[[Student Page]] [[Student Page]] [[Student Page]]&lt;br /&gt;
&lt;br /&gt;
The [https://docs.google.com/document/d/1Z0ui9HkyBsitcQuD5YYYp4JyTgSHmZFy6MoaOHyKAlI/edit group discussion]&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
{{2017ANAT2341 footer}}&lt;br /&gt;
&lt;br /&gt;
===Subheading===&lt;br /&gt;
[[File:Chicken embryo E-cad and P-cad gastrulation.png|500px]]&lt;br /&gt;
&lt;br /&gt;
embryo&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/sites/gquery?term=embryo ''embryo'']&lt;br /&gt;
&lt;br /&gt;
notochord&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/pubmed?term=notochord ''notochord'']&lt;br /&gt;
&lt;br /&gt;
References&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;28786202&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Peer Reviews=&lt;br /&gt;
==Group 1==&lt;br /&gt;
The most obvious flaw was the lack of polish in formatting of some of the page. Bullet points are only so useful when it comes to writing a wiki page, instead of taking notes. The page is unfinished, but, the content included especially in the &amp;quot;Development of Cerebral Cortex&amp;quot; and &amp;quot;Abnormalities associated with Cerebral Cortex Development&amp;quot; was extensive and well done. The large table that linked the development with the time period was very useful and the choice of bolding key words allowed the main idea in the paragraph to be quickly understood from a glance. The use of images very much enhanced the descriptions and checker-like the layout of the different abnormalities was refreshing. Some subheadings, such as the Anatomy and Function of the cerebral cortex, could be elaborated on but the overall structure of the page is logical and fluid, and the writing is clear and concise without being superficial.&lt;br /&gt;
&lt;br /&gt;
==Group 2==&lt;br /&gt;
The introduction is clear and well-thought-out; simple enough that the layman can understand but comprehensive enough to lead logically into the more extensive information on the page. Perhaps a discussion of the kidney's function ought to be included with the description of kidney structure. Kidney development; the choice of that particular style of formatting runs a risk of not tying the development with the timeline but the small table at the top serves well to stop that, even if it is a little of a hassle moving back and forth to keep up. The content was well-written and appropriate in voice and depth of knowledge. Visually well-presented with figures appropriately explained. Developmental abnormalities were covered well, and although bullet points may not be the best way to present the information, it allowed for the key points to be understood very quickly and effectively. The transition from topic to topic was logical and flowed appropriately. Some aspects of the page must of course be filled out but overall a well-rounded, well-structured and informative page. Well done.&lt;br /&gt;
&lt;br /&gt;
==Group 3==&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_2&amp;diff=311224</id>
		<title>Talk:2017 Group Project 2</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_2&amp;diff=311224"/>
		<updated>2017-10-11T23:30:11Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Reviews */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
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&amp;lt;!-- Do not remove template above from the project discussion page --&amp;gt;&lt;br /&gt;
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[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 2 below are some starting places.&lt;br /&gt;
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{{Renal Links}}&lt;br /&gt;
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PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Renal+Development ''Renal Development''] | [http://www.ncbi.nlm.nih.gov/pubmed?term=Kidney+Development ''Kidney Development'']&lt;br /&gt;
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BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Renal+Development ''Renal Development'']&lt;br /&gt;
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Recent papers&lt;br /&gt;
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&amp;lt;pubmed limit=5&amp;gt;Renal+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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Yay.&lt;br /&gt;
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[[User:Z5178275|Z5178275]] ([[User talk:Z5178275|talk]]) 16:48, 10 August 2017 (AEST) I'm keen to do anything, but I think the brain is a little to complex for me. It also seems like a lot of other groups want to do that as well.&lt;br /&gt;
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Cynthia here, I don't want to do the brain lol. I don't mind anything else though&lt;br /&gt;
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[[User:Z5076039|Z5076039]] ([[User talk:Z5076039|talk]]) 17:03, 10 August 2017 (AEST)&lt;br /&gt;
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==Peer Reviews==&lt;br /&gt;
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A really well-written and well presented wiki. The information was simplified and therefore was easy to comprehend. The use of images throughout the wiki was highly useful as they provided a visual reference point and enhanced the information presented.&lt;br /&gt;
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A few things to work on include, take out the links that have been scattered through some of the paragraphs, either reference them with a number (footnote style) or include them in the list at the end. Simplify the section on kidney Blood supply. In the Abnormalities section of the wiki, there is a list of some of the main congenital defects that occur in kidneys, however not all of these dot-points are expanded on. Maybe you could include some more abnormalities that relate to the list or specifically mention that only a selected few are going to be expanded on. The current research section may need some more attention. Overall, the layout is fantastic and well done on a great wiki.&lt;br /&gt;
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This page is very informative and easy to read. I like the way it begins with the anatomy of the kidney in the developed human, and then progresses through its embryological development. The inclusion of developmental timeline table aids the flow of the page. Images are well integrated into the page with informative descriptions, however are not correctly referenced and do include the suitable Copyright statement or Student Image Template. &lt;br /&gt;
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The 'stages of nephron development' subheading includes numbered bullet points, but would appear more finished by using the Wiki bullet points. In the &amp;quot;Genes expressed&amp;quot; section it would be beneficial if the terms RET and GDNF were expanded on. The 'Blood Supply' section is clearly unfinished, but will require in text citations and images would help it to read easier. &lt;br /&gt;
The page references well, but many sections are still unfinished. The page would benefit from a glossary at the end, and the &amp;quot;General info on the renal system&amp;quot; section should be included higher up on the page, or integrated into one of the other sections such as under the &amp;quot;Kidney&amp;quot; heading. This page is very easy to read, but still needs some work.&lt;br /&gt;
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References should be cited correctly, i.e. don’t leave the links in the paragraphs and use proper citation. The images used should include references, copyright statements as well as the Student Image template required. If there are copyright images the team could be innovative and use their own diagrams to display structures. Use references for the ‘Timeline of Kidney Embryology’ to show that a variety of sources were used to complete the table. Current Research and Future Questions subheading is incomplete. Glossary of terms could be used to explain certain words, for example explaining in simple terms what GDNF and RET are. &lt;br /&gt;
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Subheadings and content that have been used show a good understanding of the topic area. The team has bolded important words in relation to the kidney structure. The team has also placed a description under the images which allows readers to understand what the image is showing. The use of a table of ‘Timeline of Kidney’ allows readers to understand the content of the wikipage easily (maybe add images to the table). The team has shown comprehensive research; however, they need to show more referencing of sources to display the research that they have done. &lt;br /&gt;
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Overall this seems like a very well put together project and is very informative and easy to follow, and enjoyable to read. There is an appropriate balance of both text and visual diagrams, which greatly helped my understanding of the development of the kidneys. Figure 4 appears to be missing a reference. I do think perhaps an animation to explain nephron development may add additional clarity, and would provide another level of interaction for the reader. Perhaps also think about adding a student drawn diagram. The table is a great way to display the developmental stages in an easy to read manner. &lt;br /&gt;
The ‘blood supply’ section appears to be copy and paste which I assume will be rewritten? The section on current research is simply a list of PubMed links, and should be expanded to display content that is informative to the reader. Likewise, ‘questions for the future’ and ‘general info on the renal system’ remain as headings without any accompanying information. I think the questions for the future could be an interesting section, however general info I would think will have been covered elsewhere in the project. &lt;br /&gt;
The topic has clearly been researched well, and is well referenced, with most references being from scientific papers. &lt;br /&gt;
All in all I think this is a high quality project, that will only require a few additional tweaks to take it to the next level. &lt;br /&gt;
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There is a lot of good information on this page and it is easy to read and understand. The table that introduces the developmental timetable of kidney development is a quick, clear way to introduce the topic. Bolding the anatomical structures is a good way to emphasize the key information of the kidney anatomy. &lt;br /&gt;
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The information on the page is represented relatively clearly, but a couple of fixes could add clarity. In the description of the Mesonephric stage, the embryological feature, the nephrogenic chord is first introduced as the nephrogenic chord, then referred to as the nephrogenic duct in the next paragraph. Using the same words to describe the same feature makes it less confusing for the reader. Adding a picture to the “Blood Supply” section would also help visualize the kidney vasculature. There is some information about signalling factors in “Nephron Development” that seems oddly placed and may function better in the “Genes Expressed” section. In “Genes Expressed” there is an introduction of two genes, RET and GDNF. RET is clearly the focus of the section but more information about GDNF would benefit this section. Also, making clear what type of molecules RET and GDNF are (receptors, ligands, transcription factors, etc.) and explaining the mechanism of their interaction would make this section clearer. &lt;br /&gt;
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There are a couple of subheadings at the end of the project that need information in them, pictures that need copyright information and summary when you click on them, in-text citations that need to be added, and basic spelling and grammatical mistakes, all of which can be fixed with some simple editing. The information is solid, the abnormalities section is very good, and the discussion of current research “Can kidney disease be associated with nephron number?” is a good way to end the project. Overall good project. &lt;br /&gt;
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The page flows very well and is easy to read. However, there is incorrect citing or no citing at all for images and texts which can trigger copyright issues, in some sections (mostly the beginning) of the page. The structure and anatomical position is extremely easy to read and comprehend, as well as the use of a table for development. Id advise to insert more images for development and the remaining sections to help the reader visualise the process instead of being overwhelmed by the information. Developmental abnormalities seem to contain information not necessarily needed. Maybe add the 5 paragraphs above &amp;quot;Kidney developmental abnormalities are diverse and they correspond to defects at different stages of kidney development&amp;quot; statement in a separate research topic. Good use of images for abnormalities though. Overall, the page is quite informative and has been researched effectively. It could be improved by slight tweaks in format aforementioned and correct referencing.&lt;br /&gt;
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Structure and use of headings is clear and very easy to follow with a good flow. There is good implementation of labelled diagrams all throughout in sections where they are needed which is not only visually appealing, but also well balanced in regards to the amount of text included. References are not included with most of the images; also, whereas some areas are well referenced with in-text citations, other sections lack any form of references. The information is easy to read and understand due to its conciseness and use of numbering as well as shortened paragraphs. However, the initial introduction lacks a cohesive essence as the second sentence on the placenta seems out of place and unrelated to the first sentence. Also in the introduction, the references need to be entered in appropriately as the links aren’t in the form of in text references. Good use of questions as subheadings under “Current Research” as it provides an overview of the topic and peaks the curiosity of the reader – also adding to the enjoyment and ease of reading the research. Overall, well-structured page which is easy to read and is well-organised. &lt;br /&gt;
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I found the introduction to the kidney didn't flow very nicely and each sentence and paragraph were just points added in. Also, the grammar and punctuation in the introduction paragraph needs to be edited. The final thing that needs to be altered in the introduction paragraph is the links that have just been placed in. I'm not sure if they are the references but if so they need to be referenced correctly. The anatomical position and kidney structure are written really well! The only improvement I could make is with figure one and two reference them within the writing e.g. &amp;quot;Their inner structure can be divided into 2 main areas: the outer cortex, and the inner medulla, as illustrated in Figure 2&amp;quot;, otherwise this section is really great. The timeline of the kidney embryology is good - basic outline which makes it easy to follow such a complex process. To make the page flow in a more succinct manner I think it would be good to put the kidney timeline under the kidney development heading instead of separating the two as the kidney development information expands on the timeline really well. The kidney development information is really good, and I think the images really complete it. However, the link at the end of nephrogenesis needs to be referenced correctly with intext. Also under blood supply, it says &amp;quot;THIS IS COPY AND PASTE&amp;quot; so I'm not sure if that's copied off another page or your own notes but that needs to be fixed. The abnormality section was really good and current research is a really interesting thing to include, that section just needs some more information which I'm sure you guys are already on top of! Overall its a really great page, good effort.&lt;br /&gt;
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I believe the headings chosen cover a sufficient amount of points you need in order to describe kidney development! &lt;br /&gt;
Referencing needs to be changed, its easy to use the code on the wiki cheat sheet and that automatically makes a reference for you! &lt;br /&gt;
When describing position, explain what retroperitoneal means, its not commonly known and also Thoracic 12 (T12) so people know what T12 refers too. &lt;br /&gt;
For images, you need to find the copyright information and reference them properly, Mark has step by step instructions on what needs to be included in the image description. There aren’t many references in the first section of the page, it would benefit if you included some. Under nephrogenesis, point 3, you can find the articles pubmed ID and add the reference in that way instead of manually doing it. &lt;br /&gt;
For developmental abnormalities, I feel like this could be explained better, it gets technical straight away and this can become quite confusing. &lt;br /&gt;
Current research and questions need to be worked on but I’m sure that’s whats intended. &lt;br /&gt;
Overall I think the content on this page is very relevant to kidney development and it was interesting to read. The two major things you should fix are image copyright and references and intext referencing.&lt;br /&gt;
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The introduction was a clear overview of the kidney, its main parts and its role. The connection to embryological development is great because it ties in with the rest of the page. The only note here is that the references need to be properly referenced, not just pasted with the link. The anatomical position and kidney structure parts were good because there wasn’t too much text and it only served to complement the diagrams. This is a good section to put before kidney embryology as we can understand what is developing as the embryo grows.&lt;br /&gt;
The timeline of kidney embryology was very brief. This is not bad considering you go into kidney development in more detail in the next section. However, I think another column for images would be worthwhile for the reader to visualise each stage or week of development.&lt;br /&gt;
Again, there are a few referencing errors that I’m sure you’ll rectify soon. There is a good use of references in nephron development. You’ve also clearly noted the copy and paste of the blood supply section. For this part, I would strongly recommend some diagrams because vasculature can be quite complicated to understand with just text.&lt;br /&gt;
The subheading, “Developmental abnormalities”, had a good chunk of research at the beginning that gave an overview of types of abnormalities before exploring three in detail. There was also a good amount of referencing. Clearly, the current research subheading is underdeveloped but there seems to be many articles that you will explore.&lt;br /&gt;
The reference list will be more reflective of your research once you fix some of those referencing errors.&lt;br /&gt;
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Good project page that goes through almost everything required for the page – the Current Research and Future questions section is lacking context though. The project is well written and easy to understand. Some sections have a better layout than others, so maybe you can work on making the same layout for the whole page. Some sections also have the wrong formatting of references, but other sections have perfect formatting. You must be careful with copy-pasting (Blood supply section) text into your project page without giving a reference from where you copy pasted the text from.  Some of the pictures on the page also need more information on the image page itself like copyright information. It is good that you have added figure number to your pictures and a little description of it – this helps the reader to understand the context. &lt;br /&gt;
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*'''The introduction''' to the Kidney is a really good, informative section. You need to change the format of your references in this section though. The layout might be a little bit confusing since there is a title “Kidney Structure” is in the middle of the page due to the pictures on each site. &lt;br /&gt;
*'''Nephron development and The developmental Abnormalities:''' These sections have a different layout compared to the earlier sections. It’s a lot of text, so try to make it look a bit more comfortable for the reader to go through. Maybe you can try to make the layout similar to some of the other sections and give the page a better flow.&lt;br /&gt;
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This page presents nicely and very easy to read. In the introduction section, instead of pasting those references, put them in pubmed reference properly so they can be put automatically into the references. They have introduced good and enough information on the anatomy of the kidney. It was not fully referenced in the kidney development section but it was well written in this section with informative pictures and figures. It could be easier to direct the text to its picture accordingly. The timeline would be more beneficial if pictures were included. Nice and shot subheadings. In the abnormalities section, brief paragraphs with well-referenced starting off nicely. Pictures and texts are presented fairly good and are easy to see without a mess, but some of the terms were hard to understand e.g.&amp;quot;when the left and right kidneys fuse at their lower poles by a '''parenchymal isthmus''' located ventral to the abdominal aorta, forming a &amp;quot;U&amp;quot; shape&amp;quot;, maybe have a glossary section at the end of the page. A lot of references in this section is a bonus indicating it was researched well. In the current research section, majority is a list of article links which I assume they are not yet touched on at this state, which is ok. But make sure to have 2-3 journal articles in this section. A few of future question along the way if you have any would be great. Overall, it is a nice written page, looking forward to see this as a whole!&lt;br /&gt;
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This wikipage is easy to read and the details provided was informative. The amount of text in each section was just nice and wasnt too overwhelming or insufficient, which was good. Overall, I noticed that the references could be improved. Instead of adding the link at the bottom, the team should use the code to reference such as in the section &amp;quot;Nephron development&amp;quot;. Although the use of photos were really helpful and the choice of photos were great in the context they were added in, they were generally inconsistent in either description, reference or copyright information, which should be added to all photos. The anatomical position and kidney structure had clear and concise information and was easily understandable. The timeline of kidney embryology was really nice and I like how it was all 1-2 sentences long, making it really readable. In the section of developmental abnormalities, there is a large amount of text in the beginning that doesnt belong to any abnormality. Perhaps a subheading &amp;quot;Congenital Abnormalities of the Kidney and Urinary Tract&amp;quot; could be added to make it clearer as to what the text is about. Good use of image in each abnormalities though. The article appears to be unfinished but I'm assuming the team will be completing it after this peer review. To sum up, I like the readability of this wikipage and the images chosen, however, referencing and image descriptions could be further looked at for an even better page!&lt;br /&gt;
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Overall, this project page is easy to read. Most of the information provided is very concise and specific. For the anatomical position and kidney structure, do remember to add in the references in the text. Before using the short form, do include the full name. For example Thoracic 12 (T12) instead of T12. I really appreciate the timeline of development table as it provides a brief overview before moving onto the details. The section of kidney development is well done with good subheadings to help with the flow of the content. However, more images or videos can be included for better understanding. Again, for the “nephrogenesis” and “ascension” and “genes expressed” section, its lacking references. For the developmental abnormalities, maybe a subheading could be used to categorise the first few paragraphs of information as it was hard to understand the flow of the content. Since it was mentioned that “there are defects in different stages of kidney development”, the team could use this as a basis in arranging the information. Perhaps, the team could assign one abnormality for each stage of the kidney development. I think that would help the section have a better flow. The team have also stated that the information for blood supply and current research is still ongoing. For the images, some images are lacking referencing, the copyright statement and also a brief description explaining the image. This team has kept their page simple and easy to understand. With a few more added information and slight tweaks, It would be a really good page.&lt;br /&gt;
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This page is really impressive for its organisation and balanced ratio of texts to images. There is a nice structure and flow in each different sections, this caught my attention and I read through most of the sections without any problems. All of the images were also labelled appropriately, the key words were formatted in bold and certain definitions were stated. These all helped in keeping the page really interesting and organised. A list of abnormalities and its causes were also stated in a very neat and informative matter with bullet points and images. It was nice to see that the research question was relevant and thought provoking. &lt;br /&gt;
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Some paragraphs were not referenced especially the first paragraphs in each section. In-text citations should be changed into superscripts in some sections. This page contained really visually appealing images however, some images were not referenced and/or it didn't state the copyright message that states it can be reused with no issues. Some of the headings (e.g. 'Stages in nephron formation' and 'Common congenital kidney defects') were in an italics format, this could be changed into another sub-sub heading or maybe increase its font size. Blood supply section should be reviewed, summarised and referenced appropriately.&lt;br /&gt;
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Information about the kidney development were mostly sourced from reputable journals articles that was published quite recently. However, the reference list section should be reviewed to keep the referencing format consistent. At the moment, it has APA format and some have different format I am not familiar with.&lt;br /&gt;
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The layout of this webpage is extremely clear and engaging. The use of diagrams and tables makes the page more appealing to read. I like how the diagrams are split between the left and right sides of the page, the symmetry makes the project aesthetically pleasing. I also think the use of headings and subheadings makes the page well structured and easy to follow. &lt;br /&gt;
All the material seems to be relevant and informative. The information and diagrams seem to be well referenced. I think that some paragraphs such as bloody supply and developmental abnormalities need to be broken up as the one large paragraph of text is not appealing to read, however this is understandable as the project is not completed yet. Incorporating diagrams, YouTube videos or perhaps collapsible windows in these sections could be beneficial. Another suggestion for this page would be to make the overall title of ‘Kidney’ larger and clearer, perhaps include a diagram of the kidney with the title to make it more attractive.&lt;br /&gt;
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Organization of the page is done really well, especially for Nephrogenesis and the different stages involved. There is a lot of good detail in each section, specifically the abnormalities section (it may help to break down the introduction of the abnormalities with an image however).  The subheadings included show a good knowledge of the topic and guide the reader through kidney development. Good support of ideas using helpful images and timeline table of kidney development. I think the page would be more complete if the current research, questions for the future, and general info on the renal system were complete.  Also, it may make more sense to put general information at the beginning to orient the reader (depending on what the “general info” entails).  Some animal models and examples of signals involved in the “Genes Expressed” section would also help complete the page.  For the images, there should be copyright information added, a description of the image, and the proper reference.&lt;br /&gt;
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The introduction is clear and well-thought-out; simple enough that the layman can understand but comprehensive enough to lead logically into the more extensive information on the page. Perhaps a discussion of the kidney's function ought to be included with the description of kidney structure. Kidney development; the choice of that particular style of formatting runs a risk of not tying the development with the timeline but the small table at the top serves well to stop that, even if it is a little of a hassle moving back and forth to keep up. The content was well-written and appropriate in voice and depth of knowledge. Visually well-presented with figures appropriately explained. Developmental abnormalities were covered well, and although bullet points may not be the best way to present the information, it allowed for the key points to be understood very quickly and effectively. The transition from topic to topic was logical and flowed appropriately. Some aspects of the page must of course be filled out but overall a well-rounded, well-structured and informative page.&lt;br /&gt;
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This peer review is based on the relevant dot points of the ‘Group Assessment Criteria’, as well as subheadings suggested by Mark. This information can be found on the student page. &lt;br /&gt;
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{| border=&amp;quot;1&amp;quot; align=&amp;quot;left&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
|Criteria&lt;br /&gt;
|Strengths&lt;br /&gt;
|Weaknesses&lt;br /&gt;
|-&lt;br /&gt;
| 1. The choice of content shows a good understanding of the topic area&lt;br /&gt;
| The embryology timeline is well written and very informative. It gives the reader a general understanding of the process of kidney development before each stage of development is covered in detail.&lt;br /&gt;
&lt;br /&gt;
The topic of ‘kidney development’ is described clearly and in detail. The well-structured subheadings make this section of the wiki page easier to follow. The chosen figures also enhance the information presented, and facilitate the readers understanding. &lt;br /&gt;
&lt;br /&gt;
The brief introduction to the anatomy of the kidney provides a nice introduction to the topic, and helps the reader understand the basics. &lt;br /&gt;
| The wiki page is missing several important areas of information:&lt;br /&gt;
*There is no section covering key historical discoveries relevant development of the kidneys.  &lt;br /&gt;
*There is no section on animal models that have been used to advance scientific understanding of kidney development&lt;br /&gt;
*The page lacks a glossary of terms &lt;br /&gt;
&lt;br /&gt;
Even though some information regarding signalling processes has been integrated into the 'kidney development’ section, the wiki page may benefit from a section entirely dedicated to signalling processes (this is one of Mark’s recommended sub-headings)&lt;br /&gt;
&lt;br /&gt;
There is currently very little information regarding current research on the wiki page – this section needs some work.&lt;br /&gt;
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Although the heading “future questions” has been added to the wiki page, there is no information associated with it. &lt;br /&gt;
|-&lt;br /&gt;
|2. Content is correctly cited and referenced&lt;br /&gt;
|There have been attempts at referencing throughout the assignment. A reference list has been produced and appears mostly correct. References have not been repeated throughout the list. &lt;br /&gt;
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The reference list is comprised mainly of peer-reviewed primary research articles.  &lt;br /&gt;
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Some images have been referenced correctly – see ‘figure 3’.&lt;br /&gt;
|Overall, referencing throughout the wiki page is poor. Some sections completely lack referencing (see ‘kidney structure’, ‘genes expressed’). Other sections have only 1 link attached to them (see ‘nephrogenesis’). Any information that is not original (in idea or structure) needs proper sentence-by-sentence citations. The most well-referenced section is the introduction to ‘developmental abnormalities’, and that still contains some uncited material.  &lt;br /&gt;
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Try not to rely on only one source of information per section (see ‘nephrogenesis’). Try to find a variety of research articles to source your material from. This will increase the quality and reliability of the information in the wiki page. &lt;br /&gt;
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Many of the images have been cited incorrectly and used without permission (see ‘figure 1’ and ‘figure 2’) Remember to include the full reference, the original summary and the copyright license information for each image. &lt;br /&gt;
|-&lt;br /&gt;
| 3. The wiki has an element of teaching at a peer level&lt;br /&gt;
|The information presented is mostly at a level appropriate for peers. Some background information has been provided to aid in the reader’s understanding. &lt;br /&gt;
The chosen visual aids make some of the more complex ideas easier to comprehend (see ‘figure 3’). Some of the images also contain helpful descriptions that aid in understanding of the material (see ‘figure 3’ and ‘figure 8’) &lt;br /&gt;
|Many of the acronyms and terms used in this assignment are either poorly explained, or not explained at all. By including a glossary, the reader will be able to understand some of the more difficult subject areas.&lt;br /&gt;
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No student-drawn diagrams have been included in the wiki page. Try to include some hand-drawn images, as well as other devices (e.g. tables, analogies) to aid the reader.   &lt;br /&gt;
|-&lt;br /&gt;
|4. Relates the topic and content of the Wiki entry to learning aims of embryology&lt;br /&gt;
|The ‘Kidney development’ section was well-structured and was covered in great detail. &lt;br /&gt;
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Developmental signaling processes were addressed, which is another important learning aim of embryology.&lt;br /&gt;
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Current research regarding kidney development has been mentioned.  &lt;br /&gt;
|There has been no discussion of key discoveries regarding kidney development.&lt;br /&gt;
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Although a thorough understanding of certain topics areas has been demonstrated, certain areas (such as current research) still need improvement. &lt;br /&gt;
|-&lt;br /&gt;
|5. The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic&lt;br /&gt;
|Certain aspects have been well researched such as anatomy of the kidney, kidney development and developmental abnormalities. &lt;br /&gt;
|No links to other pages on the UNSW embryology wiki have been included. Try linking this wiki page to other aspects of the embryology wiki. &lt;br /&gt;
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The small number of sources cited in the reference list demonstrates a poor and narrow approach to researching this topic. A greater library of sources should be used to develop this page (mainly primary research articles).&lt;br /&gt;
|}&lt;br /&gt;
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&amp;lt;b&amp;gt;Strengths:&amp;lt;/b&amp;gt; &amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	The wiki page appears to explore a variety of topics regarding the development of the kidney, ranging from topics such as nephrogenesis, ascension of the kidneys, the importance of gene expression in kidney development and also abnormalities associated with development. Furthermore, all topics are relevant to kidney development (criteria 1). In addition a variety of images and tables have been utilized alongside the written-text (criteria 2). This helps present information to students who prefer to learn visually. &amp;lt;br&amp;gt; &amp;lt;br&amp;gt;&lt;br /&gt;
•	Within the wiki page, a broad variety of references have been included, all of which appear to be recent. All sources included appear to be correctly cited and referenced in-text, thus the authors of the page have clearly satisfied criteria 3. &amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	It was also great how the authors have not only discussed abnormalities associated with development, but have also investigated current research being conducted into this particular area of embryonic development. Thus, the authors are on track to fulfilling criteria 5 of the assessment. A possible area to investigate may be to examine whether certain abnormalities may be treated through the application of stem cell therapy for example.&amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
&amp;lt;b&amp;gt;Areas of improvement:&amp;lt;/b&amp;gt; &amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	The authors may wish to include videos which may help reinforce information presented within the wiki page. Videos may revolve around the stages of development of the kidney and may appeal to peers who prefer a learning style focused on visual explanation of concepts (criteria 4). &amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	The authors may also explore research previously conducted into this field which has allowed our understanding of renal development to grow. Thus authors may include a timeline showing discoveries over the years which have contributed to our understanding. &amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	The topic labelled “blood supply” should also include images to perhaps show the vascular map of arteries and veins which branch out towards the kidney.  &amp;lt;br&amp;gt;&amp;lt;br&amp;gt;&lt;br /&gt;
•	Authors may also wish to create a subheading titled “signaling” in order to describe the signaling processes involved in renal development. Another key improvement would be for the authors to provide a more detailed description of the genes involved in renal development, very few genes have been listed under this subheading.&lt;br /&gt;
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Grade: CREDIT&lt;br /&gt;
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General Comment:&lt;br /&gt;
Most of the sections on the page have been done well, but some areas still need improvement.&lt;br /&gt;
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		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_1&amp;diff=311222</id>
		<title>Talk:2017 Group Project 1</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_1&amp;diff=311222"/>
		<updated>2017-10-11T23:27:46Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Peer Reviews */&lt;/p&gt;
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=Cerebral Cortex=&lt;br /&gt;
==Introduction==&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0024757/ [[User:Z5177691|Z5177691]] ([[User talk:Z5177691|talk]]) 22:37, 23 August 2017 (AEST)&lt;br /&gt;
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==Lobes and Function==&lt;br /&gt;
4 Lobes: parietal, temporal, frontal, occipital&lt;br /&gt;
Video Overview: [https://www.khanacademy.org/science/health-and-medicine/human-anatomy-and-physiology/nervous-system-introduction/v/cerebral-cortex &amp;quot;Cerebral Histology&amp;quot;]&lt;br /&gt;
[[User:Z5177691|Z5177691]] ([[User talk:Z5177691|talk]]) 22:32, 23 August 2017 (AEST)&lt;br /&gt;
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==Neocortical Development==&lt;br /&gt;
Nature article: https://www.nature.com/nrn/journal/v9/n2/full/nrn2252.html [[User:Z5177691|Z5177691]] ([[User talk:Z5177691|talk]]) 22:57, 23 August 2017 (AEST)&lt;br /&gt;
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===6 Layers===&lt;br /&gt;
Layers I, II, III, IV, V, VI (see [http://www.ruf.rice.edu/~lngbrain/Sidhya/ &amp;quot;Cortical Layer Review&amp;quot;] [[User:Z5177691|Z5177691]] ([[User talk:Z5177691|talk]]) 22:57, 23 August 2017 (AEST)&lt;br /&gt;
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==Anatomy and Function== &lt;br /&gt;
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to do: &lt;br /&gt;
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-change from dot points &lt;br /&gt;
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-add images &lt;br /&gt;
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-references &lt;br /&gt;
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-finish function information &lt;br /&gt;
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===Cell Types===&lt;br /&gt;
http://www.ruf.rice.edu/~lngbrain/Sidhya/  [[User:Z5177691|Z5177691]] ([[User talk:Z5177691|talk]]) 22:57, 23 August 2017 (AEST)&lt;br /&gt;
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==Abnormalities==&lt;br /&gt;
PubMed Article: [https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0024757/ &amp;quot;Developmental Disorders&amp;quot;] [[User:Z5177691|Z5177691]] ([[User talk:Z5177691|talk]]) 22:41, 23 August 2017 (AEST)&lt;br /&gt;
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=Peer Reviews=&lt;br /&gt;
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This page is very well structured and sequential. It provides a very detailed explanation of development under chronological subheadings. Subpages under images are well informed, but some images lack a proper Copyright phrase and Student Image Template to indicate reproducibility. On the main page, some subheadings need to be capitalised (formatting) and student signatures need to be provided on relevant sections, rather than student numbers . The &amp;quot;Anatomy of the Cerebral Cortex&amp;quot; section is filled with dot points, and could be improved using paragraphs, images and Wiki formatting. The layout of the Abnormalities section could be improved, by changing the headings and subheadings. The images and videos on the page are all very relevant to the topic, but I don't think the screenshots from youtube are appropriate of reputable. The page could benefit from a glossary list and 'Future Research' section. However, the reference list was well constructed. Overall the the page addresses the brief very well.&lt;br /&gt;
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Be careful in how the sentences are expressed for example in the introduction ‘the cerebral cortex is actually the outermost layer’; avoid using ‘actually’ in this sentence. Don’t forget to remove the student numbers from the posts. Minor grammatical errors; no use of commas in long sentences. The images do include copyright however the team has forgotten to place the Student Image Template that is required. The team should add a small description of the images that are on their webpage so readers will see immediately what the image is showing. The team could do a further questions subheading or an animal model subheading to explore more on the research of the Cerebral Cortex. &lt;br /&gt;
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Subheadings and content that have been used show a good understanding of the topic area. The use of dot points where necessary are done well which makes the project easier to understand and read through. The use of tables to demonstrate the ‘Timeline of Corticogenesis’ is done comprehensively; maybe an image for each day that is explained should be added to show consistency (as only the last row has an image). The team has used their own diagrams which shows that the team was innovative in displaying their research. The references used are cited correctly, however, there are links at the bottom where they need to fix up and place it under references. &lt;br /&gt;
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Overall, the page is has nice structuring making it relatively easy to follow. But they are missing major topics necessary including historical discoveries, developmental signalling processes, current research and animal models. The introduction was short and concise, which provided a relevant amount of background knowledge. The anatomy and functions of the cerebral cortex could be put before the development so that it ties in with the introduction. The images and videos were relevant to the topic, which aided in understanding the content. However, labelling, adding a description and citing is necessary for images and videos which has not been done. A table would be a great feature for the timeline because right now its annoying to read and has a messy, unfinished look. References need fixing.&lt;br /&gt;
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The page has good structure and formatting, however there is a significant unfinished touch. Anatomy of the Cerebral Cortex heading could place all the information in a table to make it easier to read as well as images to help the viewer visualise the process. Maybe remove the student numbers because they are unnecessary and make the page look not as professional. figures and tables need to be labelled as well as referencing and copyright claims. The diagram under the statement &amp;quot;Migration and division of all six layers of the cortex is completed during the third trimester. Each layer has distinct synaptic connections and cell types that contribute to the specific functions of the cortex.&amp;quot; needs to be further explained because I had a hard time understanding the image and what each section meant. The video is a nice touch to help understand the function and placement of the cerebral cortex. Developmental abnormalities was well written, easy to understand and flowed nicely.&lt;br /&gt;
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Well-structured and provides a vast amount of background information on the functions and structure of the cortex before delving into the details of development. However, the anatomy of the cerebral cortex and the layers are difficult to understand due to heavy use of dot points – perhaps images would be of good use in this section. There is consistently limited evidence of in-text references or citations throughout the information (rather than at the beginning of some of the sections) which makes it harder to link or follow where information was gathered. Headings are concise and easy to follow however the “other info to add” subheading under “Anatomy of the Cerebral Cortex” needs to be reworded for efficiency. Under the subheading “A) Disorders due to …” the disorders are inconsistently numbered – a 2 needs to be placed with “Hemimegalencephaly” as well as 8 with Schizencephaly. Functions of the cerebral cortex is hard to follow as dot points are used with lacking descriptions or expansion. Perhaps further discussing the actions of each functional area would provide more sufficient information in this part. &lt;br /&gt;
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The layout is looking very good, pictures could be a little smaller. I like the choice of headings, they explain well what is going to be talked about. I feel like you need to add headings like animal models and current research needs to be fixed but I’m sure that’s what is intended. I have some minor points for some of the headings: &lt;br /&gt;
Early development: &lt;br /&gt;
Spelling: Rhomboncephalon, and the instead of three at the beginning of a paragraph. Overall this heading was covered well&lt;br /&gt;
Development of cerebral cortex:&lt;br /&gt;
With images, you can add figure titles and this could make your page flow better!! Maybe expand a bit more on the key developmental zones in the human cortex, a brief explanation of what happens could help. The table is very well explained, however for E50-55 I can’t see a reference for all the information, also for the picture in the table for E50-55, you haven’t copied the copyright information so you should add that so it can be used in the page and also add the student template. I really like the drawn picture, but again a figure description would be helpful.  This section is very well done. &lt;br /&gt;
Anatomy of the cerebral cortex&lt;br /&gt;
Some great points but needs to be broken up into paragraphs. Your Wikipedia link for the image is a good image however you should find the original, I recognize it from Cajal’s drawings so I think it could be in a paper about the cerebellum with Cajal. You have good ideas for this heading, also maybe add another image. &lt;br /&gt;
Functions of the cerebral cortex&lt;br /&gt;
For functional areas, I think a 2 sentence description of each area would be good and maybe a picture for reference. &lt;br /&gt;
Abnormalities&lt;br /&gt;
Intext referencing would be better. For images, add the student template to each!! Im not entirely sure how I feel about the youtube screenshots as images, maybe use one but try and find some in research articles aswell. &lt;br /&gt;
Overall, I think you’ve done a really good job at summarizing abnormalities.&lt;br /&gt;
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The introduction was a good opening to the Cortex page as it gives a brief overview and understanding of the cortex generally. The next subheading, “Early development of the Brain”, provides of a simple and clear explanation of the early development process however images would be a great addition to help visualise the text. Try having a look at some images that were shown to us in previous lectures on the brain development where it showed the neural plate, neuroectoderm and subsequent developments. &lt;br /&gt;
The next subheading, “Development of Cerebral Cortex”, would probably do better to be called “Later Development of Cerebral Cortex” as it would be a seamless flow from the previous subheading of “Early development…”. It was good that a labelled image was used and information was added for explanation. It helped orient me as I was going on to read about the timeline of corticogenesis. The timeline was detailed and the use of bold helped highlight key terms. However, I would suggest making another column for images on each day. Visual reinforcement just makes the information easier to absorb and make more sense.&lt;br /&gt;
The subheading, “Anatomy of the Cerebral Cortex”, is clearly in the editing process. I would just once again definitely recommend the use of images in this section, both hand-drawn diagrams and labelled images from the internet. I thought the use of a video was a clever way to cover the cerebral cortex functions. A bit of general text that briefly covers the functions of the main parts would be a good addition in this section, as a segue into the video.&lt;br /&gt;
The “Abnormalities” subheading was a good balance of text and images. It was easier to read because it was split into categories. I would only suggest that you mention at the beginning of the section that abnormalities associated with the cerebral cortex development can be divided into the following categories… I can see the references were placed at the beginning of the section and I’m assuming that is temporary. It is better if they are dispersed within the text where appropriate. There are a good bunch of references but you could probably aim for 25-30 for this page.&lt;br /&gt;
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This page needs some more information about current research, signaling processes, future questions and references to animal models. It would also be good with a table or quick overview of developmental origin. There has been a good use of pictures and tables. The setup of the section about abnormalities is really good. This page needs to use more references during the sections and not only at the start of a section. A glossary list would also be good for the reader to understand the page. &lt;br /&gt;
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*'''Introduction''': Gives a quick knowledge of the cerebral cortex. A picture would be good to support this introduction and maybe a bit more description of the different terms. This section also needs references.&lt;br /&gt;
*'''Early Development:''' Good setup with bulleting. I find some of the context a bit confusing to read - especially these two sentences &amp;quot;From there three primary vesicles, there is a further division at the anterior extremity of the medullary canal into five secondary vesicles during week five&amp;quot; and &amp;quot;During the fifth week, the embryonic brain undergoes rapid growth folding the neural tube and consequently resulting in three brain flexures&amp;quot; Maybe you can rephrase this. &lt;br /&gt;
*'''Development of Cerebral Cortex:''' Good section! Good overview. &lt;br /&gt;
*'''Timeline of Corticogenesis:''' Please give a short introduction of what Corticogenesis and Neurogenesis means. Good picture supporting the E50-55, maybe you can put this picture already in the section called &amp;quot;Key developmental zones in the human cortex&amp;quot; since this is the first time we get introduced to the different zones and plates and it would give a better basic knowledge before getting into Corticogenesis. &lt;br /&gt;
*'''Anatomy and Function of the Cerebral Cortex''': These two sections should maybe be earlier on the project page together with the introduction since it's a basic understanding of the Cerebral Cortex. Both sections look a bit messy, try to work on making it more simple and easier to read - it kind of looks like personal notes and not a proper information site :-) These sections also need some references. The video in this section gives a good understanding. Good idea putting a video on the page.&lt;br /&gt;
*'''Abnormalities associated with Cerebral Cortex Development:''' This section is really good. Great overview of the different scenarios and a lot of pictures to support the reading. Instead of mentioning all the references in the start of the section, you should add the specific reference used for each subsection, this will make it easier for the reader to look up references for specific sections.&lt;br /&gt;
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In the introduction section, it was not referenced where the information facts are from. This section should introduce a brief information on the topic, what you are going to discuss on the whole wiki page, introduce current researches and animal models to support the new findings and understandings. Also, don't use &amp;quot;actually&amp;quot; in the sentence. &lt;br /&gt;
On the page, It is better to write in full sentences instead of dot points as I've seen a lot of them and include any of scientific words in the glossary section at the end of the page. Where you've inserted picture, it will be clearer to also include it within the text in brackets for example (Figure 1). &lt;br /&gt;
Any figures or pictures on this page needs references as well. &lt;br /&gt;
In the abnormality section, it is well written with supporting pictures, but in my opinion, it is easier to read if the the figures/pictures are on the same side and texts on the other side instead of alternating. This section was very thoroughly referenced too. I think a small paragraph under the heading introducing the different type of disorders before going into greater details. &lt;br /&gt;
Don't focus too much on the anatomy as I can see this section is not finished nor written in paragraph and no pictures or figures, would be better to swap anatomy with some other embryology discussion for example, signalling processes.&lt;br /&gt;
Touch on current researches, animal model if any and future questions as they were not seen on the page. Also include a glossary table. References section is looking good but more is needed.&lt;br /&gt;
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Overall, a really informative and well-written wiki. The information was well presented and was understandable. The abnormalities section of the wiki, was particularly well done, as it was a good idea to group each abnormality with the disruption of the main event that lead to the abnormality, as it informs the reader that different abnormalities arise from a disruption of different processes that occur in the development of the cerebral cortex. The diagrams and pictures were useful as it functions as a reference point.&lt;br /&gt;
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Overall, the layout was good, however maybe use more of a dot-point layout in the Anatomy section and maybe add some diagrams of pictures to enhance the information given. Also the sub-title &amp;quot;what is it?&amp;quot; is probably not needed as the introduction itself suggests that you will be describing what the cerebral cortex is and what is does. The Functions of Cerebral cortex may also need a bit more text as the video should just be a supplement rather than the main source for information in that section. Overall, well done as it was an informative and well written wiki.&lt;br /&gt;
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Overall I find the information provided to be concise and easy to understand. The introduction was great in giving us a brief overview of page. The layout of the early development of the brain and the development of the cerebral cortex was really nice. I like the use of bullet points as this makes it easier to read. Also good amount of referencing is seen in this area. The use of the table is also a nice touch to the page and I like the picture used for E50-55. However, it could help to have another column with pictures for each row. That would help with the understanding of the text. For the anatomy of the cerebral cortex, it seems a little messy and hard to read as it is too point form. Perhaps these could be phrased into proper sentences with certain parts placed into bullet points to make it easier to read. Also, with the anatomy, pictures would be very helpful to aid in the explanation. For the functions of the cerebral cortex, it lists the functional areas but not the functions of those areas. Although it is stated in the video, which is a nice addition to the page, this could be improved by adding short sentences that state these functions that were mentioned as well. For Sections 1.4 and 1.5, references are also needed to state where the information was obtained from. The abnormalities section provides detailed explanations of the various disorders associated with the development of the cerebral cortex. There is also a good amount of pictures used. One thing I noticed was the references which was placed on the top of the section instead of throughout the text.&lt;br /&gt;
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Overall, the page has a good structure and flow with good headings and subheadings. The information provided was concise and easy to comprehend. The introduction provides a brief overview and sufficient background knowledge about the cerebral cortex. I like how the team thought of mentioning about the early development of the brain before narrowing it down to the cerebral cortex. However these two sections do not seem to flow well. Maybe you could have 2-3 sentences that could help ease into the development of the cerebral cortex. I really love the timeline of corticogenesis. This part has been done really well. One minor improvement that could be made is to add images under each embryonic stage instead of just the last stage to better aid the reader into understanding the development. Also, a brief description of what corticogenesis is could be included before the table. For these two sections, there were a good amount of references.&lt;br /&gt;
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For the anatomy of the cerebral cortex, it seems a little messy and hard to understand as its written in point forms. Perhaps, the dot points could be changed to proper sentences with histological images to tie it together. For the functions of the cerebral cortex, I think you could use a table to list down the areas and then provide a brief description of the functions of that particular part. The video is a good addition to the page. These two sections are lacking citations and references.The abnormalities section was well done. However, the citations should be added within the text instead of at the top of the page. Since there are a lot of abnormalities, maybe the team could list in a few sentences about all the abnormalities that they are going to discuss to have a better start to the section. For the images that are used on this page, the images should be labelled as “figure 1” or “table 1”. Maybe, sections on the “animal models” and “current research” could be added to wrap the page up.&lt;br /&gt;
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Overall the project was very good and clear. Pictures were well placed and bullet points spaced out information, making the page easy to look at and follow. The layout of the beginning and end sections with the short paragraphs and interspersed bullet points broke up the information and highlighted key facts. The introduction was a good overview of the page, including a quick summary of the anatomy, function, and development of the cerebral cortex. &lt;br /&gt;
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There were some basic grammatical and spelling errors (e.g. “neurons” is spelled wrong under the subheading “Layer 4”), but for the most part did not take away from the clarity of the page. One sentence, “From there three primary vesicles, there is a further division at the anterior extremity of the medullary canal into five secondary vesicles during week five,” seems to be missing something at the beginning that would increase clarity. &lt;br /&gt;
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Some pictures had a lot of information in the summary when clicking on them while others lacked sufficient information. Some pictures that could benefit from more information are Corticogenesis of mouse and humans.jpeg, SBH.png, Disorders of Cortical Formation2.png, Symptoms of microcephaly.png, Hemimegalencephaly.png, and SchizencephalicBrain.jpg. These pictures are relevant to the topic and are pretty self-explanatory so this does not take away much clarity from the page but for the parameters of the project, additional summary should be added. The picture Stage22 HPA2L.jpg has good information in the summary but it is oddly structured. FASface.jpeg does not have any copyright information included. Having Gray754.png displayed on the page rather than as a link would look better. &lt;br /&gt;
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The video describing the functions of the cerebral cortex was a good introduction to that topic. The video was easy to watch and understand. The first video about corpus callosum agenesis was a good introduction to the topic, but the second video about corpus callosum agenesis was long and the lecturer was hard to understand. That subheading would benefit from a brief description of that topic rather that a long video explanation. &lt;br /&gt;
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The switch from a mix of bullets and short paragraphs to all bullet points in Anatomy of the Cerebral Cortex makes the page look less cohesive. The last bullet point in Layer 4 is hard to understand and the last 2 bullet points in Layer 5 would flow better if they were combined. The information in these sections are good and relatively easy to follow. &lt;br /&gt;
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Overall the project is very good. The table explaining the timetable of cortex development is a clear way to break down the topic. Breaking down the information of abnormal development into what went wrong in the embryology (e.g. migration problems vs. differentiation problems) highlights importance of embryology in congenital disorders. There is a lot of information about the abnormal development of the cortex but could use some information about past and current research and animal studies. Reference list at the end looks good but the in-text citations of abnormal development should be interspersed with the information rather than all at the beginning. &lt;br /&gt;
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The chosen headings for the development of the cerebral cortex were very suitable to highlight the key topics in providing a page of summarised information. It was then easy to navigate through the page using the shortcuts and finding information. Although, there was one sub sub heading “Timeline of Corticogenesis” that was formatted to be in bold while the rest were not. &lt;br /&gt;
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The disorders listed seems to be really interesting and it covers the whole spectrum of the case abnormalities. But I suggest to get rid of the letter bullets (e.g. A), B), C) ) for the breakdown of the abnormalities. &lt;br /&gt;
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The introduction had a quick and concise text, however, an image of the cerebellum would be suitable in this section on the side. While the sub sub heading stated that the introduction section will talk about the features of a cerebellum, a paragraph about the development and its stages were written down in this section as well. This could be moved into the ‘Early Development of the Brain’ subheading underneath. Bullet points of the brain layers as well as a diagram would be helpful for the visualisation of the brain.&lt;br /&gt;
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For the sections that explain the development in specific weeks, a table would be advisable to make it neater and easier to look at. Also, an image was left inside the table grids and it was confusing whether it was meant to be there or not. Perhaps adding a photo gallery showing the stages at the bottom of the table would be better.&lt;br /&gt;
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Hand drawn diagrams were really precise, neat and was very visually appealing. It was taking up all the space and unless it is intentional, I suggest to resize the drawing into a smaller one that fits the page as well as the accompanying text and content of the drawing.&lt;br /&gt;
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The variety of visual aids were really entertaining and were referenced properly.&lt;br /&gt;
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Finally, the reference list at the bottom of the page did not have a consistent format. It was mostly APA format however the others looked like a different format.&lt;br /&gt;
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The most obvious flaw was the lack of polish in formatting of some of the page. Bullet points are only so useful when it comes to writing a wiki page, instead of taking notes. The page is unfinished, but, the content included especially in the &amp;quot;Development of Cerebral Cortex&amp;quot; and &amp;quot;Abnormalities associated with Cerebral Cortex Development&amp;quot; was extensive and well done. The large table that linked the development with the time period was very useful and the choice of bolding key words allowed the main idea in the paragraph to be quickly understood from a glance. The use of images very much enhanced the descriptions and checker-like the layout of the different abnormalities was refreshing. Some subheadings, such as the Anatomy and Function of the cerebral cortex, could be elaborated on but the overall structure of the page is logical and fluid, and the writing is clear and concise without being superficial.&lt;br /&gt;
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&amp;lt;b&amp;gt;Strengths:&amp;lt;/b&amp;gt; &amp;lt;br&amp;gt; &amp;lt;br&amp;gt;&lt;br /&gt;
•	The page has an excellent structure covering a broad variety of topics regarding the cerebral cortex. It was great to see how you also explored abnormalities associated with the cerebral cortex. Furthermore the use of various subheadings and headings related to cerebral cortex development meets criteria 1 and 2 of the assessment. &amp;lt;br&amp;gt;&lt;br /&gt;
•	The presentation of the wiki page was excellent in that a variety of images, videos and tables were utilized. The use of such sources of information helps present information in a much more clear and concise manner, whilst also providing a thorough explanation to visual learners. Hence the wiki page has an element of teaching at a peer level (criteria 4 is satisfied). &amp;lt;br&amp;gt;&lt;br /&gt;
•	A large number of references have also been included within the wiki page, a characteristic which helps increase the reliability of information presented. Furthermore, most sources are recent which another great characteristic. Thus, it appears that the group has satisfied criteria 3 for the assessment. &amp;lt;br&amp;gt;&lt;br /&gt;
•	Each topic appears to show a significant amount of detail which is excellent. In addition, the use of images alongside the text is a great tool as the audience is able to better visualize the concept being described. &amp;lt;br&amp;gt;&lt;br /&gt;
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&amp;lt;b&amp;gt;Areas of improvement: &amp;lt;/b&amp;gt; &amp;lt;br&amp;gt;&lt;br /&gt;
•	Although you have provided a variety of recent references, to improve you may avoid using sources as old as 1977 as results presented from this study may be outdated. &amp;lt;br&amp;gt;&lt;br /&gt;
•	It was excellent that the functional areas of the brain were listed, however to improve you may wish to elaborate on the specific functions of these areas. You may also explore how abnormalities of these areas during development may impact upon the behaviour of the individual following birth &amp;lt;br&amp;gt;&lt;br /&gt;
•	Whilst a variety of topics have been covered, you may wish to also describe the importance of signaling throughout the process of cortical development. For example, you may investigate different growth factors and receptors involved in the process. &amp;lt;br&amp;gt;&lt;br /&gt;
•	Another possible improvement would be to perhaps include a timeline of different researchers who contributed to the in-depth understanding of the developing cortex that we have today. You may also describe what each researcher discovered. &amp;lt;br&amp;gt;&lt;br /&gt;
•	In order to completely satisfy criteria 5, you may wish to conduct further research beyond the scope of formal teaching activities. For example you may explore the contribution of animal models towards our understanding of cortical development. &amp;lt;br&amp;gt;&lt;br /&gt;
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This peer review is based on the relevant dot points of the ‘Group Assessment Criteria’, as well as subheadings suggested by Mark. This information can be found on the student page. &lt;br /&gt;
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{| border=&amp;quot;1&amp;quot; align=&amp;quot;left&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
|Criteria&lt;br /&gt;
|Strengths&lt;br /&gt;
|Weaknesses&lt;br /&gt;
|-&lt;br /&gt;
| 1. The choice of content shows a good understanding of the topic area&lt;br /&gt;
| The developmental origin of the cerebral cortex is addressed well under the sub-heading ‘Early development of the brain’. &lt;br /&gt;
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The development timeline of the cerebral cortex is described clearly and in detail in the table of the ‘Timeline of corticogenesis’.&lt;br /&gt;
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Abnormal development of the cerebral cortex and the associated conditions are covered in an immense amount of detail. The accompanying images and videos enhance the written information, as well as making it easier for the reader to comprehend. In addition, the sub-headings of this section compartmentalize the congenital diseases in a logical manner that highlights the link between abnormal development and specific diseases. &lt;br /&gt;
| There are several key topic areas missing from the page:&lt;br /&gt;
*There is no section covering key historical discoveries relevant to the cerebral cortex and its embryological development. &lt;br /&gt;
*There is no information relating to developmental signalling processes &lt;br /&gt;
*There is no section on current research in fields relevant to the embryological development of the cerebral cortex. &lt;br /&gt;
*There is no section on animal models that have been used to advance scientific understanding of the cerebral cortex. &lt;br /&gt;
*There is no section on future questions regarding the development of the cerebral cortex. &lt;br /&gt;
*A glossary of terms has not been included. &lt;br /&gt;
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Some sections that have been included are somewhat irrelevant to the subject matter. For example, there is a large (unfinished) section on the anatomy and functions of the cerebral cortex. While it is important to provide a bit of an anatomical background on the subject, it shouldn’t be a major focus of this assignment. Focus more on the sections mentioned above, and keep the project focused on the embryology of the cerebral cortex. &lt;br /&gt;
|-&lt;br /&gt;
|2. Content is correctly cited and referenced&lt;br /&gt;
|There have been attempts at referencing throughout the assignment. A reference list has been produced and appears mostly correct. References have not been repeated throughout the list. &lt;br /&gt;
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Peer-reviewed primary research articles have been used in this assignment.  &lt;br /&gt;
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The student-drawn image has been cited correctly, as have most of the images used in the ‘abnormal development’ section. &lt;br /&gt;
|Overall, referencing in this assignment is very poor. Most of the content is completely devoid of any references (see ‘introduction’, ‘anatomy of the cortex’ and ‘abnormal development), and sections that have been referenced have been referenced “by paragraph” (see ‘timeline of corticogenesis’)&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Many of the sources used in this assignment are inappropriate and/or unreliable. Try to rely more on primary research articles and less on textbooks or websites. &lt;br /&gt;
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Many of the images have been cited incorrectly and used without permission. Remember to include the full reference, the original summary and the copyright license information for each image. &lt;br /&gt;
|-&lt;br /&gt;
|3. The wiki has an element of teaching at a peer level&lt;br /&gt;
|The information presented is mostly at a level appropriate for peers. Images and hand-drawn diagrams have been included to facilitate the readers understanding of the subject matter. Some of the images contain useful descriptions of the subject matter, and aid in understanding of the topic. &lt;br /&gt;
|Many of the acronyms and terms used in this assignment are not well explained. Include a glossary of terms to make some of the content easier to follow and understand. &lt;br /&gt;
|-&lt;br /&gt;
|4. Relates the topic and content of the Wiki entry to learning aims of embryology&lt;br /&gt;
|The development of the cerebral cortex was covered extensively, which is a very important learning aim of embryology. &lt;br /&gt;
|There are certain learning aims of embryology that have not been included in this assignment, such as developmental signaling processes (see criteria 1 for more information). There has been no discussion of relevant historical or current research (adding in the subheadings “key developments” and “current research” would help rectify this).&lt;br /&gt;
|-&lt;br /&gt;
|5. The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic&lt;br /&gt;
|Certain aspects have been researched and presented well (such as embryological development). &lt;br /&gt;
&lt;br /&gt;
Links to other pages of the UNSW embryology wiki have been included, however they have been used as references rather than just links. &lt;br /&gt;
|Information from the UNSW embryology wiki has been used as direct sources of information. Instead they should be included to relate this particular wiki page to other areas of learning. &lt;br /&gt;
&lt;br /&gt;
The small number of sources cited in the reference list demonstrates a poor and narrow approach to researching this topic. A greater library of sources should be used to create this page (mainly primary research articles).&lt;br /&gt;
|}&lt;br /&gt;
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Grade: FAIL&lt;br /&gt;
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General Comment:&lt;br /&gt;
While some aspects of the wiki page have been done well, the page is largely unfinished. Many sections still need to be added, and others are in need of improvement.&lt;br /&gt;
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----&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311220</id>
		<title>User:Z5113034</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=User:Z5113034&amp;diff=311220"/>
		<updated>2017-10-11T23:24:53Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341ProjectGroup2017table}}&lt;br /&gt;
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Here is the [[Student Page]] demonstration page I showed in the Practical class.&lt;br /&gt;
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Use this page to practice editing and don't forget to add a topic to the [[2017 Group Project 6]] page.&lt;br /&gt;
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[[Student Page]] [[Student Page]] [[Student Page]]&lt;br /&gt;
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The [https://docs.google.com/document/d/1Z0ui9HkyBsitcQuD5YYYp4JyTgSHmZFy6MoaOHyKAlI/edit group discussion]&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
{{2017ANAT2341 footer}}&lt;br /&gt;
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===Subheading===&lt;br /&gt;
[[File:Chicken embryo E-cad and P-cad gastrulation.png|500px]]&lt;br /&gt;
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embryo&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/sites/gquery?term=embryo ''embryo'']&lt;br /&gt;
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notochord&lt;br /&gt;
[http://www.ncbi.nlm.nih.gov/pubmed?term=notochord ''notochord'']&lt;br /&gt;
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References&lt;br /&gt;
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&amp;lt;pubmed&amp;gt;28786202&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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=Peer Reviews=&lt;br /&gt;
==Group 1==&lt;br /&gt;
The most obvious flaw was the lack of polish in formatting of some of the page. Bullet points are only so useful when it comes to writing a wiki page, instead of taking notes. The page is unfinished, but, the content included especially in the &amp;quot;Development of Cerebral Cortex&amp;quot; and &amp;quot;Abnormalities associated with Cerebral Cortex Development&amp;quot; was extensive and well done. The large table that linked the development with the time period was very useful and the choice of bolding key words allowed the main idea in the paragraph to be quickly understood from a glance. The use of images very much enhanced the descriptions and checker-like the layout of the different abnormalities was refreshing. Some subheadings, such as the Anatomy and Function of the cerebral cortex, could be elaborated on but the overall structure of the page is logical and fluid, and the writing is clear and concise without being superficial.&lt;br /&gt;
&lt;br /&gt;
==Group 2==&lt;br /&gt;
The introduction is clear and well-thought-out; simple enough that the layman can understand but comprehensive enough to lead logically into the more extensive information on the page. Perhaps a discussion of the kidney's function ought to be included with the description of kidney structure. Kidney development; the choice of that particular style of formatting runs a risk of not tying the development with the timeline but the small table at the top serves well to stop that, even if it is a little of a hassle moving back and forth to keep up. The content was well-written and appropriate in voice and depth of knowledge. Visually well-presented with figures appropriately explained. Developmental abnormalities were covered well, and although bullet points may not be the best way to present the information, it allowed for the key points to be understood very quickly and effectively. Some aspects of the page must of course be filled out but overall a well-rounded and informative page. Well done.&lt;br /&gt;
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==Group 3==&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=310096</id>
		<title>2017 Group Project 6</title>
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		<updated>2017-10-05T06:01:27Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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=&amp;lt;span style=&amp;quot;color:#0000FF&amp;quot;&amp;gt;Cerebellum&amp;lt;/span&amp;gt;=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
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=Introduction=&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
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=Basic Anatomy of the Cerebellum=&lt;br /&gt;
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The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
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[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
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'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
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'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
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There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Neural Development== &lt;br /&gt;
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[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
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==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Cerebellar Nuclei===&lt;br /&gt;
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{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.  &amp;lt;/center&amp;gt;&lt;br /&gt;
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&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
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(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;https://www.karger.com/Article/FullText/334842&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;http://onlinelibrary.wiley.com/doi/10.1111/j.1447-0756.2008.00964.x/full&amp;lt;/ref&amp;gt;;&lt;br /&gt;
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*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
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*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
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*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
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==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
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The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Cerebellum Development=&lt;br /&gt;
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[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 4:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 5:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
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The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer (Figure 4) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
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The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;. Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cells. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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==Cellular Migration==&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the rhombic lip to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the pia mater and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer&amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref&amp;gt;https://www.researchgate.net/publication/6977220_d-Serine_signalling_in_the_brain_friend_and_foe/figures?lo=1&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
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[[File:Granule Cell and Purkinje Cell Migration.png]]&lt;br /&gt;
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Figure 6: Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cell Signaling in Cerebellar Development==&lt;br /&gt;
Many different cell signaling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  Sonic hedgehog (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The external germinal layer (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for Atoh1, a transcription factor that represses differentiation and promotes division via SHH signaling.  In a similar manner to SHH and Atoh1, the pia mater secretes Sdf1 which interacts with the receptor Cxcr4 to maintain proliferation in the EGL. Notch2 signaling and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP).  BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of Neurod1 and interaction with the extracellular matrix components of the inner EGL, vitronectin, F3, and contactin. &amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;  Granule cell migration is stimulated by D-serine secreted by the Bergmann glia.  This can be inhibited by DAAO or SR.&amp;lt;ref&amp;gt;Magalie Martineau, Gérard Baux, Jean-Pierre Mothet D-serine signalling in the brain: friend and foe. Trends Neurosci.: 2006, 29(8);481-91 PubMed 16806506&amp;lt;/ref&amp;gt;  &lt;br /&gt;
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Fibroblast Growth Factor (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of rhombomere 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Reelin is an important signaling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors VLDLR and ApoER2, adaptor protein Dab1, and many other further downstream intracellular signaling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors Hoxa2 and Otx2.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Developmental Weeks==&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
&lt;br /&gt;
Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
==Dandy-Walker Malformation==&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:DandyWalkerMalformation.jpeg|435px]]&lt;br /&gt;
&lt;br /&gt;
Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Joubert Syndrome==&lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development.&lt;br /&gt;
&lt;br /&gt;
[[File:JoubertSyndrome.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Chiari Syndrome I-III==&lt;br /&gt;
Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:ChiariMalformation.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Rhombencephalosynapsis==&lt;br /&gt;
Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum.&lt;br /&gt;
&lt;br /&gt;
[[File:Rhombencephalosynapsis.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Glossary=&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=310074</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=310074"/>
		<updated>2017-10-05T05:58:15Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
=&amp;lt;span style=&amp;quot;color:#0000FF&amp;quot;&amp;gt;Cerebellum&amp;lt;/span&amp;gt;=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons.&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref name=”PMID9735944”&amp;gt;&amp;lt;pubmed&amp;gt; 9735944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref name=”PMID27766499”&amp;gt;&amp;lt;pubmed&amp;gt; 27766499&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
There are 3 germ layers present in the early embryo; ectoderm (most distal layer), mesoderm (middle layer) and endoderm (most proximal layer). The ectoderm differentiates into the nervous system, forming the spine, peripheral nerves, cerebrum and cerebellum. It also differentiates to form tooth enamel, epidermis, and the linings of the mouth, anus, sweat glands and nostrils&amp;lt;ref name=”PMID14550785”&amp;gt;&amp;lt;pubmed&amp;gt; 14550785&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&amp;lt;/ref&amp;gt;&lt;br /&gt;
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&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.  &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
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(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;https://www.karger.com/Article/FullText/334842&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;http://onlinelibrary.wiley.com/doi/10.1111/j.1447-0756.2008.00964.x/full&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
*Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
*Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
*Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 4:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
[[File:Screen Shot 2017-10-05 at 3.29.59 pm.png|thumb|'''Figure 5:''' Cerebellum cell development: A 7 day old rat cerebellum that has been sectioned to show the 3 layers of cells - external granule layer, purkinje cells and internal granular layer (a). Showing granule cell precursors proliferating to differentiate into granule neurons (b). Cell organisation (c) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4061865&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer (Figure 4) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;. Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cells. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the rhombic lip to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the pia mater and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer&amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref&amp;gt;https://www.researchgate.net/publication/6977220_d-Serine_signalling_in_the_brain_friend_and_foe/figures?lo=1&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png]]&lt;br /&gt;
&lt;br /&gt;
Figure 6: Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cell Signaling in Cerebellar Development==&lt;br /&gt;
Many different cell signaling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  Sonic hedgehog (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The external germinal layer (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for Atoh1, a transcription factor that represses differentiation and promotes division via SHH signaling.  In a similar manner to SHH and Atoh1, the pia mater secretes Sdf1 which interacts with the receptor Cxcr4 to maintain proliferation in the EGL. Notch2 signaling and its stimulation of Atoh1 and repression of Bone Morphogenetic Protein (BMP).  BMPs are involved in arresting granule cell proliferation in the EGL and stimulating differentiation.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of Neurod1 and interaction with the extracellular matrix components of the inner EGL, vitronectin, F3, and contactin. &amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;  Granule cell migration is stimulated by D-serine secreted by the Bergmann glia.  This can be inhibited by DAAO or SR.&amp;lt;ref&amp;gt;Magalie Martineau, Gérard Baux, Jean-Pierre Mothet D-serine signalling in the brain: friend and foe. Trends Neurosci.: 2006, 29(8);481-91 PubMed 16806506&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
Fibroblast Growth Factor (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of rhombomere 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Reelin is an important signaling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors VLDLR and ApoER2, adaptor protein Dab1, and many other further downstream intracellular signaling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
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The region of rhombomere 1, a segment of the metencephalon that forms the cerebellum, is bound by the expression of the transcription factors Hoxa2 and Otx2.  Otx2 is expressed in the midbrain and the lack of Otx2 marks the rostral border of the cerebellar primordium.  Hoxa2 is expressed in the hindbrain region and lack of Hoxa2 marks the caudal border of the cerebellar primordium.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3051031&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cerebellum Developmental Weeks==&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Elements of the Cerebellar Cortex.jpeg|thumb|'''Figure 7:''' Elements of the Cerebellar Cortex, from Ramon y Cajal’s Croonian Lecture (Ramon y Cajal, 1894). Abbreviations: A, Purkinje cell; B, basket cell. The more superficially located neuron is a stellate cell; C, climbing fiber; D, Purkinje cell axon with collaterals; E, granule cell; F, parallel fiber; G, mossy fiber rosette; H, basket of the basket cell axon &amp;lt;ref&amp;gt;https://ars.els-cdn.com/content/image/1-s2.0-S0306452209002711-gr16.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
&lt;br /&gt;
Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
The mouse model is a primary model organism in the study of cerebellum development, but organisms such as Drosophila (fruit fly), C. elegans (roundworm), Saccharomyces cerevisiae (Baker's yeast), cats, dogs, and cattle are also used in some types of diseases.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;19669387&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Looking at a variety of different of organisms' cerebellar development can elucidate the evolution of the cerebellum and further understanding of cerebellar constituents.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
==Dandy-Walker Malformation==&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:DandyWalkerMalformation.jpeg|435px]]&lt;br /&gt;
&lt;br /&gt;
Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. &amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Joubert Syndrome==&lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development.&lt;br /&gt;
&lt;br /&gt;
[[File:JoubertSyndrome.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Chiari Syndrome I-III==&lt;br /&gt;
Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:ChiariMalformation.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Rhombencephalosynapsis==&lt;br /&gt;
Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum.&lt;br /&gt;
&lt;br /&gt;
[[File:Rhombencephalosynapsis.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Glossary=&lt;br /&gt;
{{Glossary}}&lt;br /&gt;
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=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309670</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309670"/>
		<updated>2017-10-05T02:30:56Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Metencephalon */&lt;/p&gt;
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=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons. &lt;br /&gt;
&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
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=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
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[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
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'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.  &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
&lt;br /&gt;
(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;https://www.karger.com/Article/FullText/334842&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
&lt;br /&gt;
(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;http://onlinelibrary.wiley.com/doi/10.1111/j.1447-0756.2008.00964.x/full&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
- Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
- Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
- Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 4:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer (Figure 4) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;. Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cells. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the rhombic lip to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the pia mater and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer&amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref&amp;gt;https://www.researchgate.net/publication/6977220_d-Serine_signalling_in_the_brain_friend_and_foe/figures?lo=1&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png]]&lt;br /&gt;
&lt;br /&gt;
Figure 5: Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;26475605&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cell Signaling in Cerebellar Development==&lt;br /&gt;
Many different cell signaling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  Sonic hedgehog (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The external germinal layer (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3263706&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for Atoh1, a transcription factor that represses differentiation and promotes division via SHH signaling.  In a similar manner to SHH and Atoh1, the pia mater secretes Sdf1 which interacts with the receptor Cxcr4 to maintain proliferation in the EGL.  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of Neurod1 and interaction with the extracellular matrix components of the inner EGL, vitronectin, F3, and contactin. &amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;  Granule cell migration is stimulated by D-serine secreted by the Bergmann glia.  This can be inhibited by DAAO or SR.&amp;lt;ref&amp;gt;Magalie Martineau, Gérard Baux, Jean-Pierre Mothet D-serine signalling in the brain: friend and foe. Trends Neurosci.: 2006, 29(8);481-91 PubMed 16806506&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
Fibroblast Growth Factor (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of rhombomere 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&amp;lt;ref&amp;gt;Thomas Butts, Mary J Green, Richard J T Wingate Development of the cerebellum: simple steps to make a 'little brain'. Development: 2014, 141(21);4031-41 PubMed 25336734&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Reelin is an important signaling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors VLDLR and ApoER2, adaptor protein Dab1, and many other further downstream intracellular signaling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Developmental Weeks==&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
&lt;br /&gt;
Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
==Dandy-Walker Malformation==&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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[[File:DandyWalkerMalformation.jpeg|435px]]&lt;br /&gt;
&lt;br /&gt;
Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. A subsection labeled “Reference” and under this the original image source, appropriate reference and all copyright information.&amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Joubert Syndrome==&lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development.&lt;br /&gt;
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[[File:JoubertSyndrome.jpg|225px]]&lt;br /&gt;
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Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Chiari Syndrome I-III==&lt;br /&gt;
Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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[[File:ChiariMalformation.jpg|225px]]&lt;br /&gt;
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Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Rhombencephalosynapsis==&lt;br /&gt;
Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum.&lt;br /&gt;
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[[File:Rhombencephalosynapsis.jpg|225px]]&lt;br /&gt;
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Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Historic Images=&lt;br /&gt;
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=Glossary=&lt;br /&gt;
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=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309568</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309568"/>
		<updated>2017-10-05T01:57:15Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Key Historical Discoveries */&lt;/p&gt;
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=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons. &lt;br /&gt;
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This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
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=Basic Anatomy of the Cerebellum=&lt;br /&gt;
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The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
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[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
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'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
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'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
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==Neural Development== &lt;br /&gt;
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[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
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==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.  &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
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(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;https://www.karger.com/Article/FullText/334842&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;http://onlinelibrary.wiley.com/doi/10.1111/j.1447-0756.2008.00964.x/full&amp;lt;/ref&amp;gt;;&lt;br /&gt;
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- Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
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- Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
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- Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
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==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
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The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Cerebellum Development=&lt;br /&gt;
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(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 4:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
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The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer (Figure 4) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
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The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;. Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cells. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cellular Migration==&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the rhombic lip to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the pia mater and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer&amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref&amp;gt;https://www.researchgate.net/publication/6977220_d-Serine_signalling_in_the_brain_friend_and_foe/figures?lo=1&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
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[[File:Granule Cell and Purkinje Cell Migration.png]]&lt;br /&gt;
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Figure 5: Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&lt;br /&gt;
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==Cell Signaling in Cerebellar Development==&lt;br /&gt;
Many different cell signaling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  Sonic hedgehog (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The external germinal layer (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263706&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for Atoh1, a transcription factor that represses differentiation and promotes division via SHH signaling.  In a similar manner to SHH and Atoh1, the pia mater secretes Sdf1 which interacts with the receptor Cxcr4 to maintain proliferation in the EGL.  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of Neurod1 and interaction with the extracellular matrix components of the inner EGL, vitronectin, F3, and contactin. &amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  Granule cell migration is stimulated by D-serine secreted by the Bergmann glia.  This can be inhibited by DAAO or SR.  &lt;br /&gt;
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Fibroblast Growth Factor (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of rhombomere 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&lt;br /&gt;
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Reelin is an important signaling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors VLDLR and ApoER2, adaptor protein Dab1, and many other further downstream intracellular signaling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cerebellum Developmental Weeks==&lt;br /&gt;
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===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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==Key Historical Discoveries==&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
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Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
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Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt; The current focus in research now leans towards connecting cerebellar function with learning, emotion and perception of time.&lt;br /&gt;
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=Animal Models=&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
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=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
==Dandy-Walker Malformation==&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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[[File:DandyWalkerMalformation.jpeg|435px]]&lt;br /&gt;
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Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. A subsection labeled “Reference” and under this the original image source, appropriate reference and all copyright information.&amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Joubert Syndrome==&lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development.&lt;br /&gt;
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[[File:JoubertSyndrome.jpg|225px]]&lt;br /&gt;
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Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Chiari Syndrome I-III==&lt;br /&gt;
Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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[[File:ChiariMalformation.jpg|225px]]&lt;br /&gt;
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Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Rhombencephalosynapsis==&lt;br /&gt;
Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum.&lt;br /&gt;
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[[File:Rhombencephalosynapsis.jpg|225px]]&lt;br /&gt;
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Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Historic Images=&lt;br /&gt;
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=Glossary=&lt;br /&gt;
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=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309528</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309528"/>
		<updated>2017-10-05T01:35:18Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Key Historical Discoveries */&lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
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=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons. &lt;br /&gt;
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This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
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=Basic Anatomy of the Cerebellum=&lt;br /&gt;
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The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
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[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
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'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
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'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
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==Neural Development== &lt;br /&gt;
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[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
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==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
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===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.  &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
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(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;https://www.karger.com/Article/FullText/334842&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;http://onlinelibrary.wiley.com/doi/10.1111/j.1447-0756.2008.00964.x/full&amp;lt;/ref&amp;gt;;&lt;br /&gt;
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- Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
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- Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
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- Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
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==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
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The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Cerebellum Development=&lt;br /&gt;
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(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 4:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
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The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer (Figure 4) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
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The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;. Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cells. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cellular Migration==&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the rhombic lip to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the pia mater and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer&amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref&amp;gt;https://www.researchgate.net/publication/6977220_d-Serine_signalling_in_the_brain_friend_and_foe/figures?lo=1&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png]]&lt;br /&gt;
&lt;br /&gt;
Figure 5: Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&lt;br /&gt;
&lt;br /&gt;
==Cell Signaling in Cerebellar Development==&lt;br /&gt;
Many different cell signaling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  Sonic hedgehog (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The external germinal layer (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263706&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for Atoh1, a transcription factor that represses differentiation and promotes division via SHH signaling.  In a similar manner to SHH and Atoh1, the pia mater secretes Sdf1 which interacts with the receptor Cxcr4 to maintain proliferation in the EGL.  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of Neurod1 and interaction with the extracellular matrix components of the inner EGL, vitronectin, F3, and contactin. &amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  Granule cell migration is stimulated by D-serine secreted by the Bergmann glia.  This can be inhibited by DAAO or SR.  &lt;br /&gt;
&lt;br /&gt;
Fibroblast Growth Factor (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of rhombomere 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&lt;br /&gt;
&lt;br /&gt;
Reelin is an important signaling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors VLDLR and ApoER2, adaptor protein Dab1, and many other further downstream intracellular signaling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Developmental Weeks==&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
 Llinas,&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
&lt;br /&gt;
Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong around the 1970's defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
==Dandy-Walker Malformation==&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:DandyWalkerMalformation.jpeg|435px]]&lt;br /&gt;
&lt;br /&gt;
Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. A subsection labeled “Reference” and under this the original image source, appropriate reference and all copyright information.&amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Joubert Syndrome==&lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development.&lt;br /&gt;
&lt;br /&gt;
[[File:JoubertSyndrome.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Chiari Syndrome I-III==&lt;br /&gt;
Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:ChiariMalformation.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Rhombencephalosynapsis==&lt;br /&gt;
Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum.&lt;br /&gt;
&lt;br /&gt;
[[File:Rhombencephalosynapsis.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Glossary=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309524</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309524"/>
		<updated>2017-10-05T01:31:07Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Key Historical Discoveries */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons. &lt;br /&gt;
&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&amp;lt;/ref&amp;gt;&lt;br /&gt;
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&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.  &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
&lt;br /&gt;
(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;https://www.karger.com/Article/FullText/334842&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;http://onlinelibrary.wiley.com/doi/10.1111/j.1447-0756.2008.00964.x/full&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
- Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
- Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
- Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 4:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer (Figure 4) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;. Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cells. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the rhombic lip to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the pia mater and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer&amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref&amp;gt;https://www.researchgate.net/publication/6977220_d-Serine_signalling_in_the_brain_friend_and_foe/figures?lo=1&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png]]&lt;br /&gt;
&lt;br /&gt;
Figure 5: Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&lt;br /&gt;
&lt;br /&gt;
==Cell Signaling in Cerebellar Development==&lt;br /&gt;
Many different cell signaling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  Sonic hedgehog (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The external germinal layer (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263706&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for Atoh1, a transcription factor that represses differentiation and promotes division via SHH signaling.  In a similar manner to SHH and Atoh1, the pia mater secretes Sdf1 which interacts with the receptor Cxcr4 to maintain proliferation in the EGL.  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of Neurod1 and interaction with the extracellular matrix components of the inner EGL, vitronectin, F3, and contactin. &amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  Granule cell migration is stimulated by D-serine secreted by the Bergmann glia.  This can be inhibited by DAAO or SR.  &lt;br /&gt;
&lt;br /&gt;
Fibroblast Growth Factor (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of rhombomere 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&lt;br /&gt;
&lt;br /&gt;
Reelin is an important signaling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors VLDLR and ApoER2, adaptor protein Dab1, and many other further downstream intracellular signaling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Developmental Weeks==&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
 Llinas,&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
&lt;br /&gt;
Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
==Dandy-Walker Malformation==&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:DandyWalkerMalformation.jpeg|435px]]&lt;br /&gt;
&lt;br /&gt;
Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. A subsection labeled “Reference” and under this the original image source, appropriate reference and all copyright information.&amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Joubert Syndrome==&lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development.&lt;br /&gt;
&lt;br /&gt;
[[File:JoubertSyndrome.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Chiari Syndrome I-III==&lt;br /&gt;
Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:ChiariMalformation.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Rhombencephalosynapsis==&lt;br /&gt;
Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum.&lt;br /&gt;
&lt;br /&gt;
[[File:Rhombencephalosynapsis.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Glossary=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309522</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309522"/>
		<updated>2017-10-05T01:29:40Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Key Historical Discoveries */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons. &lt;br /&gt;
&lt;br /&gt;
This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons. Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis&amp;lt;ref name=”PMID2535662”&amp;gt;&amp;lt;pubmed&amp;gt; 2535662&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species.&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Bergmann Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.  Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.  &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
&lt;br /&gt;
===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
&lt;br /&gt;
(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;https://www.karger.com/Article/FullText/334842&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;http://onlinelibrary.wiley.com/doi/10.1111/j.1447-0756.2008.00964.x/full&amp;lt;/ref&amp;gt;;&lt;br /&gt;
&lt;br /&gt;
- Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
&lt;br /&gt;
- Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
&lt;br /&gt;
- Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 4:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer (Figure 4) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;. Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cells. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cellular Migration==&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Granule cells migrate tangentially from the rhombic lip to form the transient structure, the external germinal layer (EGL).  The EGL consists of an outer and inner layer that is sandwiched between the pia mater and the purkinje cell layer.  During this tangential migration, granule cells extend two horizontal processes.  Granule cells move from the outer layer of the EGL to differentiate in the inner layer of the EGL.  Differentiated cells continue to move radially to the granule cell layer on the inner surface of the purkinje cell layer&amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  During radial migration, granule cells extend vertical processes and move through the purkinje cell layer on the radial processes of Bergmann glia.&amp;lt;ref&amp;gt;https://www.researchgate.net/publication/6977220_d-Serine_signalling_in_the_brain_friend_and_foe/figures?lo=1&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
===Purkinje Cells===&lt;br /&gt;
Purkinje cells originate from the ventricular neuroepithelium and migrate radially towards the pial surface.  Many studies have shown that purkinje cells use radial glia processes as a scaffold in this migration.  The movement results in a 3 to 4 cell thick layer of purkinje cells beneath the EGL.  This layer becomes 1 cell thick 1 week after birth.&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&amp;lt;/ref&amp;gt;  &lt;br /&gt;
&lt;br /&gt;
[[File:Granule Cell and Purkinje Cell Migration.png]]&lt;br /&gt;
&lt;br /&gt;
Figure 5: Granule cell (yellow) and purkinje cell (green) migration timetable in mouse cerebellum. Top shows sagittal sections of entire cerebellum. Bottom shows movement of individual cells at interface of EGL and purkinje cell layer.&lt;br /&gt;
&lt;br /&gt;
==Cell Signaling in Cerebellar Development==&lt;br /&gt;
Many different cell signaling pathways are involved with cell migration, proliferation, and differentiation in the cerebellum.  Sonic hedgehog (SHH) is particularly important in the proliferation of granule cells in the external germinal layer.  The external germinal layer (EGL) is the area of transit amplification of granule cell precursors.  This layer is transient and lies on the external surface of the cerebellum until the cells differentiate and migrate radially to their final destination in the internal granule cell layer.  SHH is secreted by the purkinje cells and acts locally, causing the granule cell precursors to undergo mitosis and Bergmann glia to differentiate.  The autocrine function of SHH on the purkinje cells is unknown. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263706&amp;lt;/ref&amp;gt;  Proliferating cells in the EGL must also be positive for Atoh1, a transcription factor that represses differentiation and promotes division via SHH signaling.  In a similar manner to SHH and Atoh1, the pia mater secretes Sdf1 which interacts with the receptor Cxcr4 to maintain proliferation in the EGL.  Cells exit proliferation and move to the inner EGL where they differentiate upon expression of Neurod1 and interaction with the extracellular matrix components of the inner EGL, vitronectin, F3, and contactin. &amp;lt;ref&amp;gt;http://dev.biologists.org/content/141/21/4031&amp;lt;/ref&amp;gt;  Granule cell migration is stimulated by D-serine secreted by the Bergmann glia.  This can be inhibited by DAAO or SR.  &lt;br /&gt;
&lt;br /&gt;
Fibroblast Growth Factor (FGF) plays a role in allocating the isthmus area of the cerebellum.  FGF8 is found in high concentrations in the rostral region of rhombomere 1 and decreased concentrations near the caudal region of rhombomere 1.  It is necessary for the formation of the vermis of the cerebellum but the cerebellar hemispheres form independently of FGF8.&lt;br /&gt;
&lt;br /&gt;
Reelin is an important signaling molecule that plays a role in many different in the developing brain.  Reelin is a glycoprotein secreted by cells in the EGL and rhombic lip and affects purkinje cells through a signal transduction pathway involving receptors VLDLR and ApoER2, adaptor protein Dab1, and many other further downstream intracellular signaling molecules.  Reelin has shown to play a role in formation of the monolayer of purkinje cells and detachment of purkinje cells from radial glia.  It may also affect other cell morphology and migration in the cerebellum.&amp;lt;ref&amp;gt;Hevner R. F. (2008) Reelin and the Cerebellum. In: Fatemi S. H. (eds) Reelin Glycoprotein. Springer, New York, NY&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Cerebellum Developmental Weeks==&lt;br /&gt;
&lt;br /&gt;
===First Trimester===&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
===Second Trimester===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
 Llinas,&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref name=”12481483”&amp;gt;&amp;lt;pubmed&amp;gt;12481483&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref name=”PMID19272426”&amp;gt;&amp;lt;pubmed&amp;gt;19272426&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Ramon y Cajal made an especially important contribution to understanding the cerebellum. He refuted Camillo Golgi's previous assertion that axons and dendrites would fuse, and also delineated the differing types of cells, most importantly of which were the mossy and climbing fibers of the cerebellum. However, this contribution could not be fully utilised until further technology was developed.&lt;br /&gt;
Olof Larsell is credited for developing a standard nomenclature for cerebellar anatomy that eventually spread world-wide, and for conducting a series of studies that illuminated our understanding of the rhombencephalon. &amp;lt;ref&amp;gt;&amp;quot;In Memoriam: Olof Larsell, 1886-1964.&amp;quot; Journal of comparative neurology 123:1-4 (1964).&amp;lt;/ref&amp;gt;&lt;br /&gt;
With the advent of electron microscopy, John Eccles and Janos Szentágothai in the 1960s managed to piece together the first complete map of the functional anatomy of the cerebellum and define the excitory and inhibitory nature of each cell type provided by Cajal. Further discoveries into the relationships between cell synapses, cell natures, and the minutiae of their structures by Jan Voogd, Olov Oscarsson and David Armstrong defined the organisation of Purkinje cells into &amp;quot;a series of longitudinal parasagittal bands&amp;quot;, the specificity of which explains the solely Purkinje-axon-output of the cerebellar cortex. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
==Dandy-Walker Malformation==&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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[[File:DandyWalkerMalformation.jpeg|435px]]&lt;br /&gt;
&lt;br /&gt;
Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. A subsection labeled “Reference” and under this the original image source, appropriate reference and all copyright information.&amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Joubert Syndrome==&lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development.&lt;br /&gt;
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[[File:JoubertSyndrome.jpg|225px]]&lt;br /&gt;
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Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Chiari Syndrome I-III==&lt;br /&gt;
Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
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[[File:ChiariMalformation.jpg|225px]]&lt;br /&gt;
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Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Rhombencephalosynapsis==&lt;br /&gt;
Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum.&lt;br /&gt;
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[[File:Rhombencephalosynapsis.jpg|225px]]&lt;br /&gt;
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Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Historic Images=&lt;br /&gt;
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=Glossary=&lt;br /&gt;
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=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309204</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=309204"/>
		<updated>2017-10-04T13:34:42Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
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=Introduction=&lt;br /&gt;
The cerebellum is a large portion of the brain that functions in coordination, balance and control, and its development occurs both prenatally and postnatally. The cerebellum underlies the occipital and temporal lobes of the cerebral cortex and constitutes to about 10% of the brains weight however contains around 50% of the neurons. &lt;br /&gt;
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This page will highlight the anatomy of the cerebellum, its developmental process, current research on the structure, animal models and abnormalities associated with it. The anatomy will discuss the distinguishable lobes and zones of the cerebellum. The anatomy of the cerebellum cannot be completely discussed without explaining the vasculature of the structure and hence this page will provide a brief overview of it. The development of the cerebellum discusses the neural development and where the cerebellum forms on the neural tube. The development will highlight how the circuitry of the post-natal cerebellum came to be from neurons(?). Hence purkinje cells, granule cells, deep nuclei cells, glia cells and cerebellar nuclei will be highlighted to discuss the developmental process. A developmental timeline of the formation of the cerebellum is also included on this page. The cerebellum is a topic of continuous research and past findings would not have been done without the use of animal models, hence current research and animal models will be discussed. The abnormalities that could happen if the cerebellum were to be affected is also highlighted.&lt;br /&gt;
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=Basic Anatomy of the Cerebellum=&lt;br /&gt;
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The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
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[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
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'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
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'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/2535662&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
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==Neural Development== &lt;br /&gt;
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[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
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==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. &amp;lt;ref&amp;gt;http://neurotransporter.org/Cerebellum.html&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology.&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
&amp;lt;ref&amp;gt;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. &amp;lt;ref&amp;gt;http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&amp;lt;/ref&amp;gt; The dentate nucleus in particular is thought to be implicated in higher level cognitive processing.  It is enlarged in primates and humans and not observed in non-mammalian species. &lt;br /&gt;
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===Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.&lt;br /&gt;
====Bergmann Glia====&lt;br /&gt;
Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. &amp;lt;ref&amp;gt;https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&amp;lt;/ref&amp;gt;&lt;br /&gt;
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====Oligodendrocytes====&lt;br /&gt;
Oligodendrocytes are glia found primarily in the white matter of the cerebellum.  These glial cells form the fatty myelin sheath that gives the white matter its color.&lt;br /&gt;
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===Cerebellar Nuclei===&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Cerebellar Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Description''' &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Fastigial Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Most medially located of the cerebellar nuclei. Receives input from the vermis and cerebellar afferents that carry vestibular, proximal somatosensory, auditory and visual information.  &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Interposed Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Consists of emboliform nucleus and globose nucleus. Interposed nuclei are situated laterally with respect to the fastigial nucleus. Receives input from intermediate zone and cerebellar afferents that carry spinal, proximal somatosensory, auditory and visual information. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Dentate Nucleus'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Largest of the cerebellar nuclei. Lateral to interposed nuclei. Receives input from lateral hemisphere and cerebellar afferents that carry information from cerebral cortex. &amp;lt;/center&amp;gt;&lt;br /&gt;
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|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Vestibular Nuclei'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Located outside cerebellum in the medulla. Considered to be cerebellar nuclei as their connectivity patterns are identical to those of cerebellar nuclei. Receive input from flocculonodular lobe and from the vestibular labyrinth.  &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
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&amp;lt;ref&amp;gt;Knierim, J. (n.d.). Chapter 5: Cerebellum. Retrieved 10 3, 2017, from Neuroscience: http://neuroscience.uth.tmc.edu/s3/chapter05.html&amp;lt;/ref&amp;gt;.&lt;br /&gt;
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==Early Brain Vesicles==&lt;br /&gt;
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===Primary Brain Vesicles===&lt;br /&gt;
[[File:Primary Brain Vesicles.jpeg]]&lt;br /&gt;
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(Week 4) 3 primary brain vesicles are formed; forebrain (prosencephalon) midbrain (mesencephalon), and hindbrain (rhombencephalon) &amp;lt;ref&amp;gt;https://www.karger.com/Article/FullText/334842&amp;lt;/ref&amp;gt;&lt;br /&gt;
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===Secondary===&lt;br /&gt;
[[File:Secondary brain vesicle.jpeg|700px]]&lt;br /&gt;
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(Week 5) 3 primary vesicles develop into 5 secondary vesicles &amp;lt;ref&amp;gt;http://onlinelibrary.wiley.com/doi/10.1111/j.1447-0756.2008.00964.x/full&amp;lt;/ref&amp;gt;;&lt;br /&gt;
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- Prosencephalon develops into telencephalon (which includes the endbrain and cerebral hemispheres) and diencephalon (located between the brain and forms an optic outgrowth)&lt;br /&gt;
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- Mesencephalon does not further develop into a secondary brain vesicle&lt;br /&gt;
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- Rhombencephalon develops into the metencephalon (behind the brain), and myelencephalon (contains medulla)&lt;br /&gt;
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==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
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The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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=Cerebellum Development=&lt;br /&gt;
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(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
[[File:Neural Circuit in the Cerebellum.jpg|thumb|'''Figure 4:''' Cerebellar neuronal circuits (A): Representation of zebrafish cerebellar neurons (B): Sagittal section of the adult zebrafish cerebellum (C): Zebrafish cerebellar structure schematic representation &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum is connected to the brain stem via three pairs of peduncles and this allows the afferent and efferent pathways to enter and exit the cerebellum. Cerebellum afferent fibers can be grouped into two major types: mossy fibers and climbing fibres. Mossy fibres contribute to most of the afferent fibres in the cerebellum and they communicate with the cerebellar nuclei neurons and with Purkinje cells through granule cells embryonically, however postnatally they displace from Purkinje cells and synapse with their adult targets, the granule cell dendrites. Whilst mossy fibres originate from numerous sites in the nervous system, climbing fibers originate exclusively from the inferior olivary nucleus. Climbing fibers directly synapse with the cerebellar nuclei and Purkinje cells, relaying information to the cerebellum from several regions. The direction of these afferent fibres to their target neurons early in development are controlled by genes and molecules &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Within the layers there are some other main neuronal cell types, the stellate and basket cells are located in the molecular layer, whilst granule, golgi and unipolar brush cells are located in the granular layer (Figure 4) &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  Among these principal neurons, there is a diverse set of interneurons which are responsible for coordinating the output of the Purkinje cells to the cerebellar nuclei.&lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;. Granule cells function in coordinating afferent input to and motor output from the cerebellum through excitatory connections with the Purkinje cells. &lt;br /&gt;
Proper cerebellum function requires well-organised neuronal connections and the integration of afferent and efferent fibres throughout the cerebellar circuit &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;4552263&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellum functions in sensorimotor, balance control and vestibular ocular reflex, however recent studies have come out and shown that the cerebellum has a wide range of cognitive functions which include speech, memory and cognitive functions &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;3213765&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Developmental Weeks==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Human Stage13 sagittal upper half01.jpg|200px|thumb| Sagittal view of superior end of embryo &amp;lt;ref&amp;gt; Hill, M.A. 2017 Embryology Human Stage13 sagittal upper half01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage13_sagittal_upper_half01.jpg&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage14 neural01.jpg|200px|thumb|Lateral view of embryo central nervous system at 5 weeks &amp;lt;ref&amp;gt;M.A. 2017 Embryology Human Stage14 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage14_neural01.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Development of cerebellum cell layer (future Purkinje cells) and choroid plexuses of the fourth and lateral ventricles &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt; 2252222&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; [[File:Human Stage21 neural01.jpg|200px|thumb|Left lateral view of embryonic CNS&amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural01.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural01.jpg&amp;lt;/ref&amp;gt;]] [[File:Human Stage21 neural02.jpg|200px|thumb|Left medial view of lateral embryonic CNS &amp;lt;ref&amp;gt;Hill, M.A. 2017 Embryology Human Stage21 neural02.jpg. Retrieved October 4, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/File:Human_Stage21_neural02.jpg&amp;lt;/ref&amp;gt;]] &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Key Historical Discoveries==&lt;br /&gt;
 Cajal, Larsell, Eccles, Voogd, Llinas, Ito.&lt;br /&gt;
Human interest in the cerebellum has persisted since even the early 1500's, where Galen, Vesalius and Varolio gave the first few attempts to fully describe the macroscopic anatomy of the cerebellum. However, it was not until the late 1700's that advances were made to gain experimental evidence for the function of the cerebellum. Luigi Rolando identified a specifically motor impact after cerebellar lesions developed, as opposed to an intellectual or sensory effect. This led to the conclusion that the cerebellum incited and managed movement. Pierre Flourens and Luigi Luciani were able to use this albeit crude experimentation to further define that the cerebellum coordinated movement instead of creating it, and also to differentiate between the short-term and long-term effects of cerebellar lesions, respectively. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt; &lt;br /&gt;
Ernesto Lugaro first defined &amp;quot;plasticity&amp;quot; as we know it in neuroscience, and also discovered the specific cells in the cerebellum that are named after him. He also furthered research into the functions of glia and defined &amp;quot;nervous conduction and transmission&amp;quot; in its current meaning. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/12481483&amp;lt;/ref&amp;gt; Joseph Babinski and Gordon Holmes further defined the exact nature of the effect of cerebellar lesions on motor control, and found loss of coordination in antagonistic muscles and also basic loss of muscle control. It was also found that the side of the cerebellum the lesion developed on, affected the same side of the body. &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/19272426&amp;lt;/ref&amp;gt; &lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
==Dandy-Walker Malformation==&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst can be seen on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other structures that can be identified on MRI scans include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:DandyWalkerMalformation.jpeg|435px]]&lt;br /&gt;
&lt;br /&gt;
Brain MRIs. Brain imaging of patients with Dandy-Walker malformation (CCM067, CCM095) and patients with normal cerebellum and posterior fossa (CCM001). A: sagittal midline T1-weighted images. B: axial T2-weighted images. A subsection labeled “Reference” and under this the original image source, appropriate reference and all copyright information.&amp;lt;ref name=”PMID PMC3667004”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3667004&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Joubert Syndrome==&lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. It is also described as the &amp;quot;molar tooth sign&amp;quot; on brain imaging, which the &amp;quot;molar tooth&amp;quot; shaped is caused by the defects in the midbrain-hindbrain development.&lt;br /&gt;
&lt;br /&gt;
[[File:JoubertSyndrome.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Brain Imaging of Joubert Syndrome: Cranial MRI showing “molar tooth sign” (arrows)&amp;lt;ref name=”PMIDPMC3896311”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3896311&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Chiari Syndrome I-III==&lt;br /&gt;
Chiari Syndrome I-III is when the structures within the posterior cranial fossa protrude into the spinal canal &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; which can affect the development and functioning of the cerebellum in the long term. Chiari Syndrome can be classified into four types. The downward shift of the cerebellar tonsils to beneath the foramen magnum is type 1 and the downward movement of the vermis, medulla oblongata and pons with the fourth ventricle is type 2 &amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. When majority of the cerebellum lies in the foramen magnum it is type 3 and when it is completely in the foramen magnum (and therefore cannot develop normally) it is type 4&amp;lt;ref name=”PMID18762395”&amp;gt;&amp;lt;pubmed&amp;gt;18762395&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
[[File:ChiariMalformation.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Cerebellar tonsils herniation on magnetic resonance imaging: Chiari malformation type I&amp;lt;ref name=”PMIDPMC4279813”&amp;gt;&amp;lt;pubmed&amp;gt;PMC4279813&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Rhombencephalosynapsis==&lt;br /&gt;
Rhombencephalosynapsis is a rare cerebellar defect whereby there is dorsal fusion of the cerebral hemispheres, fusion of dentate nuclei and superior cerebellar peduncles as well as the agenesis of the cerebella vermis &amp;lt;ref name=”PMID18155944”&amp;gt;&amp;lt;pubmed&amp;gt;18155944&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Like other mentioned abnormalities there is development delay because of the underdeveloped cerebellum.&lt;br /&gt;
&lt;br /&gt;
[[File:Rhombencephalosynapsis.jpg|225px]]&lt;br /&gt;
&lt;br /&gt;
Partial Rhombencephalosynapsis with fused upper parts of the cerebellum&amp;lt;ref name=”PMIDPMC3447431”&amp;gt;&amp;lt;pubmed&amp;gt;PMC3447431&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Current Research=&lt;br /&gt;
&lt;br /&gt;
=Animal Models=&lt;br /&gt;
==Isthmic Organiser==&lt;br /&gt;
Throughout history there have been many investigations on the cerebellum and how it has developed through research involving chicken embryos and mice. As previously mentioned the neural plate closes to form the neural tubes which have anterior-posterior (AP) and dorsal-ventral (DV) axes. Earlier experiments involving chick-quail chimera suggested that the cerebellum was derived from both midbrain and hindbrain. However, through successive gene expression and fate mapping studies, it was discovered that the anterior-most rhombomere of the hindbrain is where the cerebellum is formed from &amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Once the axes are formed the isthmic organiser (IsO) is formed which plays a vital role in establishing the anterior limit of the cerebellar territory. The IsO in other words is the mid-hindbrain boundary &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. However, the IsO does not position itself without the help of transcription factors. Studies of mouse and chicken embryos have shown that two homeo domain-containing transcription factors Otx2 and Gbx2 have an important role in positioning the isthmic organiser &amp;lt;ref name=”PMID21309081”&amp;gt;&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Surgical movement of the isthmic tissue to more anterior or posterior regions of the neural tube of 10-somite stage chick embryos led to ectopic midbrain and cerebellar structures&amp;lt;ref name=”PMID14567957”&amp;gt;&amp;lt;pubmed&amp;gt; 14567957&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;, indicating that where the IsO is placed is an important factor in establishing where the cerebellum positions.&lt;br /&gt;
z5018156&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Glossary=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=308056</id>
		<title>Talk:2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=308056"/>
		<updated>2017-10-03T10:42:23Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* z5113034 */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project discussion page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Project Starting Places=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 6 below are some starting places.&lt;br /&gt;
&lt;br /&gt;
{{Neural Links 2}}&lt;br /&gt;
&lt;br /&gt;
PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
Cerebellum: links between development, developmental disorders and motor learning; [http://journal.frontiersin.org/article/10.3389/fnana.2012.00001/full]&lt;br /&gt;
&lt;br /&gt;
Cellular commitment in the developing cerebellum [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4290586/] &lt;br /&gt;
&lt;br /&gt;
Recent papers&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed limit=5&amp;gt;Cerebellum+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the folding of the neural tubes to form the cranial and caudal region of the embryo (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
=z5114433=&lt;br /&gt;
structure&lt;br /&gt;
time course&lt;br /&gt;
functional developing&lt;br /&gt;
what cells appear when&lt;br /&gt;
&lt;br /&gt;
glial cells development&lt;br /&gt;
&lt;br /&gt;
4th ventricle &lt;br /&gt;
&lt;br /&gt;
Genes in abnormalities&lt;br /&gt;
&lt;br /&gt;
pathway of development of cere cells&lt;br /&gt;
start of as neuroblast&lt;br /&gt;
&lt;br /&gt;
=z5018156=&lt;br /&gt;
Things to remember:&lt;br /&gt;
&lt;br /&gt;
Coordinates muscular activities - walking, crawling, writing &lt;br /&gt;
&lt;br /&gt;
Embryo doesnt need the musuclar activities &lt;br /&gt;
&lt;br /&gt;
Prenatal - neurons develop to carry out those activities later on &lt;br /&gt;
&lt;br /&gt;
Postnatal - wiring up &lt;br /&gt;
&lt;br /&gt;
Neural tube  &lt;br /&gt;
&lt;br /&gt;
Comes from pontine flexure - 4th ventricle -- the cerebellum develops into this space &lt;br /&gt;
&lt;br /&gt;
Lamination of the cerebellum&lt;br /&gt;
&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pubmed/19732611 &lt;br /&gt;
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https://www.ncbi.nlm.nih.gov/pubmed/21380713&lt;br /&gt;
&lt;br /&gt;
=Z5076158=&lt;br /&gt;
==Week 7 Work== &lt;br /&gt;
What I could add: Paramotal cells, molecular layer, what cerebellum connects to, how they are remodeled postnatally Kahals research&lt;br /&gt;
https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-150-the-brainstem-metencephalon-fourth-vesicle-the-cerebellum  - good reference &lt;br /&gt;
LARSONS HUMAN EMBRYOLOGY TEXTBOOK&lt;br /&gt;
The metencephalon gives rise to the pons and the cerebellum, the adjacent rhombic lips also contribute to the development of cerebellum. The pons functions to relay signals that link both the spinal cord and cerebral cortex with the cerebellum and the cerebellum is a centre for postural and balance control. Pontine nuclei relay information from cerebrum to the cerebellum. &lt;br /&gt;
The cerebellum is first recognized as a pair of thickened cerebellar plates or cerebellar primordia. &lt;br /&gt;
Adjacent rhombic lips gives rise to Cerebellar granule cells&lt;br /&gt;
Major portion of the cerebellum consists of a narrow median swelling called the vermis and this grows faster than the flocculonodular which were the primitive part of the cerebellum and therefore becomes the dominant portion of the mature cerebellum. &lt;br /&gt;
Folding: &lt;br /&gt;
Primary fissure deepens by end of third month and divides vermis and hemispheres into a cranial anterior lobe and caudal middle lobe. Lobes divide further into lobules due to development of transverse fissures. This fissure formation and foliation continues throughout embryonic, fetal and postnatal life and this is done to increase the surface area of the cerebellar cortex. &lt;br /&gt;
2 types of grey matter present: &lt;br /&gt;
- Internal deep cerebellar nucler &lt;br /&gt;
- External cerebellar cortex &lt;br /&gt;
4 deep nuclei and all output of the cerebellar cortex is relayed through these nuclei. &lt;br /&gt;
These nuclei and cortex are produced by a process called neurogenesis and neuronal migration&lt;br /&gt;
1.	Dentate&lt;br /&gt;
2.	Globose&lt;br /&gt;
3.	Emboliform&lt;br /&gt;
4.	Fastigular &lt;br /&gt;
&lt;br /&gt;
4th month – germinal layers undergo cell division and this produces populations of cerebellar neurons. &lt;br /&gt;
•	Ventricular layer – purkinje cells, golgi cells, basket cells, stellate cells&lt;br /&gt;
•	Granule cells remaining from the cerebellar cortex (these arise from external germinal layer) &lt;br /&gt;
•	External germinal layer – primitive nuclear neurons  these migrate to form deep cerebellar nuclei&lt;br /&gt;
==Week 8 Work== &lt;br /&gt;
PAPER 1995&lt;br /&gt;
Cerebellum – about: &lt;br /&gt;
It consists of 3 layers with 2 principal classes of neurons&lt;br /&gt;
Granule cells  studies of naturally occurring mutations and targeted gene disruption that block discrete steps in development of this region&lt;br /&gt;
Development of anterior portion of neural tube involves the formation of 3 brain vesicles:&lt;br /&gt;
1.	Prosencephalon &lt;br /&gt;
2.	Mesencephalon &lt;br /&gt;
3.	Rhombencephalon&lt;br /&gt;
Division of rhombencephalon into metencephalic vesicles and myelincephalic vesicles (this forms in day 9)&lt;br /&gt;
Failure of neural tube closure creates gap along the dorsal aspect of the neural tube, which bows into a mouth-like structure as the tube bends to establish the pontine flexure. &lt;br /&gt;
Further deepening this newly formed pontine flexure, bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brainstem) fold underneath developing the cerebellum plate. &lt;br /&gt;
&lt;br /&gt;
Cells fated for cerebellum are derived from both the mesencephalon and metencephalic vesicles (rhombencephalon). Neuroepithelium of the mesencephalon generated majority of the cells in the cerebellar cortex: V-like area of mediodorsal aspect of the anlarge arose from a caudal movement of cells from the mesencephalon. &lt;br /&gt;
&lt;br /&gt;
PAPER 2014&lt;br /&gt;
Cerebellum has a very basic structure: &lt;br /&gt;
•	Monolayer of inhibitory purkinje cells sandwiched between a dense layer of excitatory granule cells&lt;br /&gt;
•	Subpiled molecular layer of granular cell axons and purkinje cell dendritic fibres&lt;br /&gt;
Granule cells receives inputs from outside the cerebellum and project to the purkinje cells, the majority of which then project to a variety of cerebellar nuclei in the white matter. &lt;br /&gt;
The area designated for the cerebellum to reside (anlage) during development was located between hindbrain and midbrain. Regulation of patterning in this early stage (E9) of development shows to be particularly important for development of the uniquely mammalian midline expanded region of the cerebellum, “vermis”. &lt;br /&gt;
&lt;br /&gt;
Specific cell types are allocated along the dorsoventral axis. For glutamatergic cells of cerebellum, remarkably prolonged establishment and an important dynamic process that takes place at most dorsal interface between neural and non-neural roof plate tissue, the rhombic lip. This phase generates the basic dichotomy between GABAergic and glutamatergic cell types that underlies the conserved Purkinje-Granule cell circuit. &lt;br /&gt;
Cell type allocation proceeds a third, distinct temporal phase of development that extends into early prenatal (up to 2 years). In this phase, the principal derivative of the rhombic lip, the granule cell precursor, accumulates over the surface of the cerebellum and undergoes further rounds of symmetric division in a process of transit amplification that exponentially expands its numbers. &lt;br /&gt;
The anlage of the cerebellum is a product of mechanisms of segmentation that establish iterated rhombomeric subdivision within the hindbrain just after neural tube closure. &lt;br /&gt;
All cells of the cerebellum arise from dorsal rhomomere, a region definitively classified by absence of the expression of Otx and Hox genes. Majority of cerebellum arises from metencephalic (rostral) hindbrain.&lt;br /&gt;
&lt;br /&gt;
=z5113034=&lt;br /&gt;
Vasculature of cerebellum originates from vertebral arteries and the arteries that arise from it. &lt;br /&gt;
&lt;br /&gt;
Metencephalon; temporary structure that differentiates into pons and cerebellum ventrally and dorsally respectively.&lt;br /&gt;
&lt;br /&gt;
Current Research&lt;br /&gt;
&lt;br /&gt;
Key discoveries during research of cerebellar development&lt;br /&gt;
&lt;br /&gt;
=Topic Selection=&lt;br /&gt;
Hi group! I am personally interested in the development of the heart! Also, are you guys happy to exchange details after the lab tomorrow? - z5018156&lt;br /&gt;
&lt;br /&gt;
Hi! Im happy to share details! And yeah heart would be interesting, but I was also thinking maybe the ear? that could be cool&lt;br /&gt;
&lt;br /&gt;
Hey, yeah I was thinking the heart- I did a course on it last semester, but i also feel its quite generic and the other groups would do something similar. Shall we wait until the end of prac and find each other? Call out number 6 LMAO (z5114433)&lt;br /&gt;
&lt;br /&gt;
Hey all! I'm pretty open about topics but I was leaning towards the eye? Unless that's too close to optom, (and it might be a popular subject too?) I'm fine with anything. Let's find each other after prac! -z5113034&lt;br /&gt;
&lt;br /&gt;
The ear sounds good as well as the eye, theres also the lungs as well! We can just make a list and then decide as a group! - z5018156&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=308042</id>
		<title>Talk:2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=308042"/>
		<updated>2017-10-03T10:19:40Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project discussion page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Project Starting Places=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 6 below are some starting places.&lt;br /&gt;
&lt;br /&gt;
{{Neural Links 2}}&lt;br /&gt;
&lt;br /&gt;
PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
Cerebellum: links between development, developmental disorders and motor learning; [http://journal.frontiersin.org/article/10.3389/fnana.2012.00001/full]&lt;br /&gt;
&lt;br /&gt;
Cellular commitment in the developing cerebellum [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4290586/] &lt;br /&gt;
&lt;br /&gt;
Recent papers&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed limit=5&amp;gt;Cerebellum+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the folding of the neural tubes to form the cranial and caudal region of the embryo (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
=z5114433=&lt;br /&gt;
structure&lt;br /&gt;
time course&lt;br /&gt;
functional developing&lt;br /&gt;
what cells appear when&lt;br /&gt;
&lt;br /&gt;
glial cells development&lt;br /&gt;
&lt;br /&gt;
4th ventricle &lt;br /&gt;
&lt;br /&gt;
Genes in abnormalities&lt;br /&gt;
&lt;br /&gt;
pathway of development of cere cells&lt;br /&gt;
start of as neuroblast&lt;br /&gt;
&lt;br /&gt;
=z5018156=&lt;br /&gt;
Things to remember:&lt;br /&gt;
&lt;br /&gt;
Coordinates muscular activities - walking, crawling, writing &lt;br /&gt;
&lt;br /&gt;
Embryo doesnt need the musuclar activities &lt;br /&gt;
&lt;br /&gt;
Prenatal - neurons develop to carry out those activities later on &lt;br /&gt;
&lt;br /&gt;
Postnatal - wiring up &lt;br /&gt;
&lt;br /&gt;
Neural tube  &lt;br /&gt;
&lt;br /&gt;
Comes from pontine flexure - 4th ventricle -- the cerebellum develops into this space &lt;br /&gt;
&lt;br /&gt;
Lamination of the cerebellum&lt;br /&gt;
&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pubmed/19732611 &lt;br /&gt;
&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pubmed/21380713&lt;br /&gt;
&lt;br /&gt;
=Z5076158=&lt;br /&gt;
==Week 7 Work== &lt;br /&gt;
What I could add: Paramotal cells, molecular layer, what cerebellum connects to, how they are remodeled postnatally Kahals research&lt;br /&gt;
https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-150-the-brainstem-metencephalon-fourth-vesicle-the-cerebellum  - good reference &lt;br /&gt;
LARSONS HUMAN EMBRYOLOGY TEXTBOOK&lt;br /&gt;
The metencephalon gives rise to the pons and the cerebellum, the adjacent rhombic lips also contribute to the development of cerebellum. The pons functions to relay signals that link both the spinal cord and cerebral cortex with the cerebellum and the cerebellum is a centre for postural and balance control. Pontine nuclei relay information from cerebrum to the cerebellum. &lt;br /&gt;
The cerebellum is first recognized as a pair of thickened cerebellar plates or cerebellar primordia. &lt;br /&gt;
Adjacent rhombic lips gives rise to Cerebellar granule cells&lt;br /&gt;
Major portion of the cerebellum consists of a narrow median swelling called the vermis and this grows faster than the flocculonodular which were the primitive part of the cerebellum and therefore becomes the dominant portion of the mature cerebellum. &lt;br /&gt;
Folding: &lt;br /&gt;
Primary fissure deepens by end of third month and divides vermis and hemispheres into a cranial anterior lobe and caudal middle lobe. Lobes divide further into lobules due to development of transverse fissures. This fissure formation and foliation continues throughout embryonic, fetal and postnatal life and this is done to increase the surface area of the cerebellar cortex. &lt;br /&gt;
2 types of grey matter present: &lt;br /&gt;
- Internal deep cerebellar nucler &lt;br /&gt;
- External cerebellar cortex &lt;br /&gt;
4 deep nuclei and all output of the cerebellar cortex is relayed through these nuclei. &lt;br /&gt;
These nuclei and cortex are produced by a process called neurogenesis and neuronal migration&lt;br /&gt;
1.	Dentate&lt;br /&gt;
2.	Globose&lt;br /&gt;
3.	Emboliform&lt;br /&gt;
4.	Fastigular &lt;br /&gt;
&lt;br /&gt;
4th month – germinal layers undergo cell division and this produces populations of cerebellar neurons. &lt;br /&gt;
•	Ventricular layer – purkinje cells, golgi cells, basket cells, stellate cells&lt;br /&gt;
•	Granule cells remaining from the cerebellar cortex (these arise from external germinal layer) &lt;br /&gt;
•	External germinal layer – primitive nuclear neurons  these migrate to form deep cerebellar nuclei&lt;br /&gt;
==Week 8 Work== &lt;br /&gt;
PAPER 1995&lt;br /&gt;
Cerebellum – about: &lt;br /&gt;
It consists of 3 layers with 2 principal classes of neurons&lt;br /&gt;
Granule cells  studies of naturally occurring mutations and targeted gene disruption that block discrete steps in development of this region&lt;br /&gt;
Development of anterior portion of neural tube involves the formation of 3 brain vesicles:&lt;br /&gt;
1.	Prosencephalon &lt;br /&gt;
2.	Mesencephalon &lt;br /&gt;
3.	Rhombencephalon&lt;br /&gt;
Division of rhombencephalon into metencephalic vesicles and myelincephalic vesicles (this forms in day 9)&lt;br /&gt;
Failure of neural tube closure creates gap along the dorsal aspect of the neural tube, which bows into a mouth-like structure as the tube bends to establish the pontine flexure. &lt;br /&gt;
Further deepening this newly formed pontine flexure, bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brainstem) fold underneath developing the cerebellum plate. &lt;br /&gt;
&lt;br /&gt;
Cells fated for cerebellum are derived from both the mesencephalon and metencephalic vesicles (rhombencephalon). Neuroepithelium of the mesencephalon generated majority of the cells in the cerebellar cortex: V-like area of mediodorsal aspect of the anlarge arose from a caudal movement of cells from the mesencephalon. &lt;br /&gt;
&lt;br /&gt;
PAPER 2014&lt;br /&gt;
Cerebellum has a very basic structure: &lt;br /&gt;
•	Monolayer of inhibitory purkinje cells sandwiched between a dense layer of excitatory granule cells&lt;br /&gt;
•	Subpiled molecular layer of granular cell axons and purkinje cell dendritic fibres&lt;br /&gt;
Granule cells receives inputs from outside the cerebellum and project to the purkinje cells, the majority of which then project to a variety of cerebellar nuclei in the white matter. &lt;br /&gt;
The area designated for the cerebellum to reside (anlage) during development was located between hindbrain and midbrain. Regulation of patterning in this early stage (E9) of development shows to be particularly important for development of the uniquely mammalian midline expanded region of the cerebellum, “vermis”. &lt;br /&gt;
&lt;br /&gt;
Specific cell types are allocated along the dorsoventral axis. For glutamatergic cells of cerebellum, remarkably prolonged establishment and an important dynamic process that takes place at most dorsal interface between neural and non-neural roof plate tissue, the rhombic lip. This phase generates the basic dichotomy between GABAergic and glutamatergic cell types that underlies the conserved Purkinje-Granule cell circuit. &lt;br /&gt;
Cell type allocation proceeds a third, distinct temporal phase of development that extends into early prenatal (up to 2 years). In this phase, the principal derivative of the rhombic lip, the granule cell precursor, accumulates over the surface of the cerebellum and undergoes further rounds of symmetric division in a process of transit amplification that exponentially expands its numbers. &lt;br /&gt;
The anlage of the cerebellum is a product of mechanisms of segmentation that establish iterated rhombomeric subdivision within the hindbrain just after neural tube closure. &lt;br /&gt;
All cells of the cerebellum arise from dorsal rhomomere, a region definitively classified by absence of the expression of Otx and Hox genes. Majority of cerebellum arises from metencephalic (rostral) hindbrain.&lt;br /&gt;
&lt;br /&gt;
=z5113034=&lt;br /&gt;
Vasculature of cerebellum originates from vertebral arteries and the arteries that arise from it. &lt;br /&gt;
&lt;br /&gt;
Metencephalon; temporary structure that differentiates into pons and cerebellum ventrally and dorsally respectively.&lt;br /&gt;
&lt;br /&gt;
=Topic Selection=&lt;br /&gt;
Hi group! I am personally interested in the development of the heart! Also, are you guys happy to exchange details after the lab tomorrow? - z5018156&lt;br /&gt;
&lt;br /&gt;
Hi! Im happy to share details! And yeah heart would be interesting, but I was also thinking maybe the ear? that could be cool&lt;br /&gt;
&lt;br /&gt;
Hey, yeah I was thinking the heart- I did a course on it last semester, but i also feel its quite generic and the other groups would do something similar. Shall we wait until the end of prac and find each other? Call out number 6 LMAO (z5114433)&lt;br /&gt;
&lt;br /&gt;
Hey all! I'm pretty open about topics but I was leaning towards the eye? Unless that's too close to optom, (and it might be a popular subject too?) I'm fine with anything. Let's find each other after prac! -z5113034&lt;br /&gt;
&lt;br /&gt;
The ear sounds good as well as the eye, theres also the lungs as well! We can just make a list and then decide as a group! - z5018156&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=307326</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=307326"/>
		<updated>2017-10-02T06:16:27Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Metencephalon */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 16:16, 14 September 2017 (AEST) OK Feedback&lt;br /&gt;
*&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/2535662&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. http://neurotransporter.org/Cerebellum.html z5177699&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology. z5177699&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31 z5177699&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&lt;br /&gt;
===Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.&lt;br /&gt;
====Bergmann Glia====&lt;br /&gt;
Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&lt;br /&gt;
====Oligodendrocytes====&lt;br /&gt;
Oligodendrocytes are glia found primarily in the white matter of the cerebellum.  These glial cells form the fatty myelin sheath that gives the white matter its color.&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
z5114433&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt; The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
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=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst is found on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other characterisations include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
 &lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Tecto-Cerebellar Dysraphism with Occipital Meningo-Encephalocele (TCD-OE) is a rare, infrequent abnormality defined by underdevelopment of the cerebellar vermis, tectal malformation, and occipital encephalocele &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. TCD-OE patients also have development delay, lack of muscle coordination and irregular breathing like individuals with JS. However, those with TCD-OE also have episodic abnormal heavy breathing (tachypnea), low muscle strength, excess digits and a hole in the eye (opsoclonus), which can be seen as abnormal development. In neuroimaging, cerebellar midline defects are identifiable (such as a cleft of the cerebellar vermis), as well as elongation of the Superior Cerebellar Peduncle (SCP), dorsal midbrain deformity, displacement of the brainstem and vertical orientation of the cerebellar hemispheres &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
Rhombencephalosynapsis is a rare, irregular cerebellar defect characterised by the failure to develop the vermis, dorsal fusion of the cerebellar hemispheres and fusion of dentate nuclei and SCP, which is seen as the keyhole-shape of the fourth ventricle in neuoroimaging &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=307324</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=307324"/>
		<updated>2017-10-02T06:15:42Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Metencephalon */&lt;/p&gt;
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&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 16:16, 14 September 2017 (AEST) OK Feedback&lt;br /&gt;
*&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
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[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
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'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
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'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
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[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/2535662&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
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==Ectoderm==&lt;br /&gt;
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==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. http://neurotransporter.org/Cerebellum.html z5177699&lt;br /&gt;
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===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology. z5177699&lt;br /&gt;
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===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31 z5177699&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
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===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&lt;br /&gt;
===Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.&lt;br /&gt;
====Bergmann Glia====&lt;br /&gt;
Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&lt;br /&gt;
====Oligodendrocytes====&lt;br /&gt;
Oligodendrocytes are glia found primarily in the white matter of the cerebellum.  These glial cells form the fatty myelin sheath that gives the white matter its color.&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
z5114433&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
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==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
The first structure that belies the future cerebellum are the rhombic lips that appear on the metencephalon of a 5-6 week old embryo. The rhombic lips are aptly rhombus-shaped and denote the perimeter between the roof plate and the main body of the rhombencephalon. The anterior pair of lips mark the site at which the cerebellum will develop. &amp;lt;ref&amp;gt;Bruce M. Carlson MD, PhD, in Human Embryology and Developmental Biology (Fifth Edition), 2014&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum&amp;lt;ref name=”PMIDPMC3179064”&amp;gt;&amp;lt;pubmed&amp;gt; PMC3179064&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst is found on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other characterisations include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres &amp;lt;ref name=”PMID21093738”&amp;gt;&amp;lt;pubmed&amp;gt; 21093738&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
 &lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, intellectual disability, respiratory disturbances and abnormal eye movement &amp;lt;ref name=”PMIDPMC2913941”&amp;gt;&amp;lt;pubmed&amp;gt;PMC2913941&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Tecto-Cerebellar Dysraphism with Occipital Meningo-Encephalocele (TCD-OE) is a rare, infrequent abnormality defined by underdevelopment of the cerebellar vermis, tectal malformation, and occipital encephalocele &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. TCD-OE patients also have development delay, lack of muscle coordination and irregular breathing like individuals with JS. However, those with TCD-OE also have episodic abnormal heavy breathing (tachypnea), low muscle strength, excess digits and a hole in the eye (opsoclonus), which can be seen as abnormal development. In neuroimaging, cerebellar midline defects are identifiable (such as a cleft of the cerebellar vermis), as well as elongation of the Superior Cerebellar Peduncle (SCP), dorsal midbrain deformity, displacement of the brainstem and vertical orientation of the cerebellar hemispheres &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
Rhombencephalosynapsis is a rare, irregular cerebellar defect characterised by the failure to develop the vermis, dorsal fusion of the cerebellar hemispheres and fusion of dentate nuclei and SCP, which is seen as the keyhole-shape of the fourth ventricle in neuoroimaging &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=307316</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=307316"/>
		<updated>2017-10-02T06:04:09Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Metencephalon */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 16:16, 14 September 2017 (AEST) OK Feedback&lt;br /&gt;
*&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/2535662&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. http://neurotransporter.org/Cerebellum.html z5177699&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology. z5177699&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31 z5177699&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&lt;br /&gt;
===Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.&lt;br /&gt;
====Bergmann Glia====&lt;br /&gt;
Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&lt;br /&gt;
====Oligodendrocytes====&lt;br /&gt;
Oligodendrocytes are glia found primarily in the white matter of the cerebellum.  These glial cells form the fatty myelin sheath that gives the white matter its color.&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
z5114433&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
The metencephalon refers to the embryonic neural structure that eventually gives rise dorsally, to the cerebellum and ventrally, to the pons. The metencephalon is the anterior part of the rhombencephalon (hindbrain) and differentiates from the posterior part of the rhombencephalon (myencephalon) at week 5 of development. &lt;br /&gt;
&lt;br /&gt;
The dorsal surface is characterised by its highly folded folia separated by grooves termed sulci. The median area is referred to as the vermis, which eventually becomes the most superior aspect of the cerebellum. &amp;lt;ref&amp;gt;Gerardo De Iuliis PhD, Dino Pulerà MScBMC, CMI, in The Dissection of Vertebrates (Second Edition), 2011&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Abnormalities found within the posterior fossa of the cranium may affect the functioning and development of the cerebellum. The abnormalities affecting the cerebellum include Dandy-Walker-Malformation, Joubert Syndrome, Tecto-Cerebllar Dysraphism and Rhombencephalosynapsis (RS). &lt;br /&gt;
&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum [find reference]) may either be elevated or rotated upwards &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.  The communication of the 4th ventricle with the midline posterior fossa cyst is found on MRI scans of DWM &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. Other characterisations include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres (reference DWM article). &lt;br /&gt;
 &lt;br /&gt;
Joubert syndrome (JS) is described as a rare inherited genetic disorder characterised by lack of muscle coordination, developmental delay, and either neonatal respiratory disturbances or abnormal eye movement &amp;lt;ref&amp;gt;https://ac-els-cdn-com.wwwproxy1.library.unsw.edu.au/S0028384314604539/1-s2.0-S0028384314604539-main.pdf?_tid=61523f80-a72e-11e7-8612-00000aacb361&amp;amp;acdnat=1506920510_1adf2cde97720bd7909ebf0873992979&amp;lt;/ref&amp;gt;. On neuroimaging, the cerebellar vermis is identified to have gone through hypoplasia (underdevelopment) or dysplasia (abnormal development) &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
Tecto-Cerebellar Dysraphism with Occipital Meningo-Encephalocele (TCD-OE) is a rare, infrequent abnormality defined by underdevelopment of the cerebellar vermis, tectal malformation, and occipital encephalocele &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. TCD-OE patients also have development delay, lack of muscle coordination and irregular breathing like individuals with JS. However, those with TCD-OE also have episodic abnormal heavy breathing (tachypnea), low muscle strength, excess digits and a hole in the eye (opsoclonus), which can be seen as abnormal development. In neuroimaging, cerebellar midline defects are identifiable (such as a cleft of the cerebellar vermis), as well as elongation of the Superior Cerebellar Peduncle (SCP), dorsal midbrain deformity, displacement of the brainstem and vertical orientation of the cerebellar hemispheres &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &lt;br /&gt;
&lt;br /&gt;
Rhombencephalosynapsis is a rare, irregular cerebellar defect characterised by the failure to develop the vermis, dorsal fusion of the cerebellar hemispheres and fusion of dentate nuclei and SCP, which is seen as the keyhole-shape of the fourth ventricle in neuoroimaging &amp;lt;ref name=”PMID22108217”&amp;gt;&amp;lt;pubmed&amp;gt;22108217&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=307308</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=307308"/>
		<updated>2017-10-02T05:26:34Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Vasculature */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 16:16, 14 September 2017 (AEST) OK Feedback&lt;br /&gt;
*&lt;br /&gt;
&lt;br /&gt;
=Basic Anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
The cerebellum has 3 distinguishable lobes; flocculonodular lobe, anterior lobe and the posterior lobe. The anterior and posterior lobe can be further divided in a midline cerebellar vermis and lateral cerebellar hemispheres (Figure 1)&lt;br /&gt;
&amp;lt;ref&amp;gt;http://www.sciencedirect.com/science/article/pii/S1364661398012108&amp;lt;/ref&amp;gt;. In a superior cerebellar view, the cerebellum contains a vermis that runs through the middle of the organ and 2 intermediate zones located laterally from the vermis (Figure 2).&lt;br /&gt;
&lt;br /&gt;
[[File:Anatomical-Lobes-of-the-Cerebellum.jpg|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 1:''' Anatomical lobes observed in the cerebellum; anterior lobe, posterior lobe and flocculonodular lobe, which is divided by two fissures – the primary fissure and posterolateral fissure &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum anatomical subdivisions.png|600px]]&lt;br /&gt;
&lt;br /&gt;
'''Figure 2:''' Superior view of the 3 cerebellar zones. The middle is the vermis. Either side of the vermis is the intermediate zone. Lateral to the intermediate zone is the lateral hemispheres. There is no difference in gross structure between the lateral hemispheres and intermediate zones. &amp;lt;ref&amp;gt;https://commons.wikimedia.org/wiki/File:CerebellumDiv.png&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
[[File:Arteries of the cerebellum.jpeg|thumb|'''Figure 3:''' Diagram of the main arteries of the cerebellum &amp;lt;ref&amp;gt;http://teachmeanatomy.info/neuro/structures/cerebellum/&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
==Vasculature== &lt;br /&gt;
The cerebellum contains 3 bilateral paired arteries which supplies this organ with oxygenated blood. These arteries all originate from the vertebrobasilar system; Superior Cerebellar Artery (SCA), Anterior Inferior Cerebellar Artery (AICA) and the Posterior inferior cerebellar artery (PICA). The SCA and AICA are branches of the basilar artery, which wraps around the anterior aspect of the pons before reaching the cerebellum. The PICA arises from the left and right vertebral artery, which form the basilar artery &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/books/NBK11042/&amp;lt;/ref&amp;gt;. The PICA and AICA combine to supply the inferior half of the cerebellum, while the SCA supplies the majority of the superior half. The PICA and SCA combine to supply the vermis &amp;lt;ref&amp;gt;https://www.ncbi.nlm.nih.gov/pubmed/2535662&amp;lt;/ref&amp;gt;. Blood is then drained by superior and inferior cerebellar veins into the superior petrosal and then straight dural venous sinuses. (Figure 3) &amp;lt;ref&amp;gt;https://www.researchgate.net/publication/309323728_Arteries_and_Veins_of_the_Cerebellum&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. http://neurotransporter.org/Cerebellum.html z5177699&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology. z5177699&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31 z5177699&lt;br /&gt;
&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&lt;br /&gt;
===Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.&lt;br /&gt;
====Bergmann Glia====&lt;br /&gt;
Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&lt;br /&gt;
====Oligodendrocytes====&lt;br /&gt;
Oligodendrocytes are glia found primarily in the white matter of the cerebellum.  These glial cells form the fatty myelin sheath that gives the white matter its color.&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
z5114433&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;2775156&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Week'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 3'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; ''Neurulation'': Notochord and somites are formed under the ectoderm. The ectoderm then forms the neural plate which then forms the neural tube and then the brain and spinal chord. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | [[File:Stage9 dorsal.jpg|200px|thumb|Early stage of neurulation]] [[File:Stage10 bf5.jpg|200px|thumb|Late stages of neurulation]]&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 4'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon, mesencephalon and rhombencephalon is developed.&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Week 5'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Prosencephalon develops into telencephalon and diencephalon. The rhombencephalon differentiates into metencephalon and myelencephalon. The metencephalon will later develop the pons and cerebellum. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''week 6'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; A pair of thickenings on the lateral side of the alar plate is formed. This is called the rhombic lip. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  7-9'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; The rhombic lip is fused medially to the midbrain. The primitive choroid plexus is fused with the cerebellar hemisphere to form the centrally located eosinophilic matrix. During this process, the inferior olive develops into a thick medulla forming a 'bulbo-pontine extension' &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks 11-12'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Cerebellar hemisphere grows in size and thickness. Laminar configuration becomes present and vermis fissures start to develop. Mechanical stress such as shear and rotation can be detected by the cerebellum, causing several deep fissures to be developed &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt; &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks  15-16'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; Nodule and flocculus is developed. Several deep fissures are formed in the vermis  which has increased in thickness similar to the hemispheres  &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;21380713&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;. &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
During the formation of the cerebellum, other brain structures may affect the development and long-term use of the brain structure. There are abnormalities affecting the cerebellum which include Dandy-Walker-Malformation, Chiari Malformation (whatever you’re going to include). &lt;br /&gt;
&lt;br /&gt;
Dandy-Walker-Malformation (DWM) includes the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa (Reference: https://www.ncbi.nlm.nih.gov/pubmed/22108217). The cerebellar vermis (found at the medial, cortico-nuclear zone of the cerebellum [find reference]) may either be elevated or rotated upwards [REFERENCE ARTICLE].  The communication of the 4th ventricle with the midline posterior fossa cyst is found on MRI scans of DWM (reference). Other characterisations include upward displacement of the tentorium and anterolateral shift of cerebellar hemispheres (reference DWM article). z5018156&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=306824</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=306824"/>
		<updated>2017-09-29T01:53:16Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Blood Supply */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 16:16, 14 September 2017 (AEST) OK Feedback&lt;br /&gt;
*&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. http://neurotransporter.org/Cerebellum.html z5177699&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology. z5177699&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31 z5177699&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&lt;br /&gt;
===Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.&lt;br /&gt;
====Bergmann Glia====&lt;br /&gt;
Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&lt;br /&gt;
====Oligodendrocytes====&lt;br /&gt;
Oligodendrocytes are glia found primarily in the white matter of the cerebellum.  These glial cells form the fatty myelin sheath that gives the white matter its color.&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
z5114433&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
The cerebellum is supplied by three bilateral pairs of arteries. Most superiorly, there is the aptly named superior cerebellar artery (SCA). Moving inferiorly, there are the left and right anterior inferior cerebellar arteries (AICA) and posterior inferior cerebellar arteries (PICA). The SCA arise from the first bifurcation of the Basilar Artery, directly inferior to the Posterior Cerebral Artery. The AICA are the most inferior branch that arises from the  Basilar Artery, and the PICA arise from the left and right Vertebral Arteries. The Vertebral Arteries are two paired arteries that join to form the Basilar Artery.&lt;br /&gt;
&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/books/NBK11042/&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pubmed/21829761&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/books/NBK11042/&lt;br /&gt;
&lt;br /&gt;
The PICA and AICA combine to supply the inferior half of the cerebellum while the SCA supplies the majority of the superior half. The center of the cerebellum is a region of large variance with regards to the exact vasculature, as it differs between individuals. &lt;br /&gt;
http://www.ajnr.org/content/ajnr/8/2/199.full.pdf USE THE IMAGE HERE&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref name=&amp;quot;PMID2775156&amp;quot;&amp;gt;&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Stage'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Historical Discoveries'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Embryonic (weeks 4-5)'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks 5-6)'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | &lt;br /&gt;
| width=&amp;quot;65&amp;quot; | &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; about &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; about &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; about&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
- Mechanical Movement of Neurones from Metencephalon&lt;br /&gt;
&lt;br /&gt;
- Number of Divisions Determines Cell Type&lt;br /&gt;
&lt;br /&gt;
- Differentiation of Specific Neurones&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
Dandy-Walker-Malformation (DWM) is the incomplete development of the cerebellar vermis with cystic dilatation of the 4th ventricle and enlargement of the posterior fossa (Reference: https://www.ncbi.nlm.nih.gov/pubmed/22108217). It primarily affects the development of the cerebellum. There are a variety of ways DWM may progress in which these include;&lt;br /&gt;
&lt;br /&gt;
-	Midline posterior fossa cyst widely communicating with the 4th ventricle&lt;br /&gt;
&lt;br /&gt;
-	Underdevelopment of the cerebellar vermis, which may be elevated and rotated upward&lt;br /&gt;
&lt;br /&gt;
-	Anterolateral displacement of normal appearing cerebellar hemispheres &lt;br /&gt;
&lt;br /&gt;
-	Upward displacement of the tentorium&lt;br /&gt;
&lt;br /&gt;
-	Enlargement of the posterior fossa&lt;br /&gt;
&lt;br /&gt;
-	Lack of patency of the foramina of Luschka and/or Magendie, &lt;br /&gt;
&lt;br /&gt;
-	Supratentorial hy- drocephalus (Reference: same article - might need to reword)&lt;br /&gt;
&lt;br /&gt;
[[PICTURE FROM ARTICLE HERE]] z5018156 &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
z5076158 could be a good article to use - https://www.ncbi.nlm.nih.gov/pubmed/22108217&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=306678</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=306678"/>
		<updated>2017-09-27T01:38:12Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Blood Supply */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 16:16, 14 September 2017 (AEST) OK Feedback&lt;br /&gt;
*&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Ectoderm==&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
&lt;br /&gt;
[[File:2 day old embryo diagram.jpeg|200px|thumb|Diagram of a 2 Day Old &lt;br /&gt;
Embryo Illustrating the Beginnings of Neural Development &amp;lt;ref&amp;gt;Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Neural Development.&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum &amp;lt;ref&amp;gt;https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'&amp;lt;/ref&amp;gt; . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Cortical Layers===&lt;br /&gt;
There are 3 major cortical layers of the cerebellum: the molecular layer, the purkinje cell layer, and the granule cell layer.  The molecular layer contains basket cells, stellate cells and the purkinje cell and Golgi cell dendrites.  The purkinje cell layer contains purkinje cell bodies and Bergmann glia.  The granule cell layer contains granule cells, mossy fibers, and Golgi cell bodies. http://neurotransporter.org/Cerebellum.html z5177699&lt;br /&gt;
&lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology. z5177699&lt;br /&gt;
&lt;br /&gt;
===Granule Cells===&lt;br /&gt;
[[File:Cerebellum Structure.jpg|500px|right|thumb|Structure of the Cerebellum &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;]]&lt;br /&gt;
Named for their small cell body, cerebellar granule cells of were discovered by Camillo Golgi and Ramon y Cajal in 1899.  Cerebellar granule cells are the most numerous cell type in the human brain.  They receive signals from mossy fibers of the pons and synapse on the fast network of dendrites of the pyramidal cells.  Cerebellar granule cells are glutamatergic and the only excitatory neurons found in the cerebellum.&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_31 z5177699&lt;br /&gt;
&lt;br /&gt;
===Deep Nuclei===&lt;br /&gt;
There are four different deep nuclei of the cerebellum: the dentate, interpositus, fastigial, and vestibular nuclei.  The dentate nucleus receives signals from the lateral purkinje cells, the interpositus nucleus receives signals from the intermediate purkinje cells, the fastigial nucleus receives signals from the medial purkinje cells, and the vestibular nucleus receives signals from the flocculonodular purkinje cells.  The deep nuclei integrate the inhibitory signals from the purkinje cells and the excitatory signals from the mossy and climbing fibers to determine their output signals. http://www.neuroanatomy.wisc.edu/cere/text/P5/intro.htm&lt;br /&gt;
===Glia===&lt;br /&gt;
Glial cells of the cerebellum were described by Ramon y Cajal in 1911.  He divided them into 3 main categories: the glia of the white matter, the astrocytes of the granule cell layer, and the Bergmann glia of the Purkinje cell layer.&lt;br /&gt;
====Bergmann Glia====&lt;br /&gt;
Also known as Goligi epithelial cells, Bergmann glia are unipolar astrocytes that have cell bodies located in the Purkinje cell layer and long processes projecting into the molecular layer.  The Bergmann glia's processes interact with the dendrites of Purkinje cells at synapses with parallel and climbing fibers.  Bergmann first characterized the long processes of cells he saw in the cerebellum of cats, dogs, and humans in 1857.  Ramon y Cajal later described these cells as &amp;quot;epithelial cells with Bergmann fibers,&amp;quot; giving the glia their name. https://link.springer.com/content/pdf/10.1046%2Fj.0022-7722.2002.00021.x.pdf&lt;br /&gt;
====Oligodendrocytes====&lt;br /&gt;
Oligodendrocytes are glia found primarily in the white matter of the cerebellum.  These glial cells form the fatty myelin sheath that gives the white matter its color.&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
z5114433&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
The cerebellum is supplied by three bilateral pairs of arteries. Most superiorly, there is the aptly named superior cerebellar artery (SCA). Moving inferiorly, there are the left and right anterior inferior cerebellar arteries (AICA) and posterior inferior cerebellar arteries (PICA). The SCA arise from the first bifurcation of the Basilar Artery, directly inferior to the Posterior Cerebral Artery. The AICA are the most inferior branch that arises from the  Basilar Artery, and the PICA arise from the left and right Vertebral Arteries. The Vertebral Arteries are two paired arteries that join to form the Basilar Artery.&lt;br /&gt;
&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/books/NBK11042/&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/pubmed/21829761&lt;br /&gt;
https://www.ncbi.nlm.nih.gov/books/NBK11042/&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
&lt;br /&gt;
As the neural tube folds, the anterior portion develops the three brain vesicles; prosencephalon, mesencephalon and rhombencephalon. The rhombencephalon then further divides into the mesencephalic and myelincephalic vesicles on embryonic day 9. The neural tube failure to close then creates a gap along the dorsal sides and this produces a mouth-like structure as the tube bends to establish the pontine flexure. The pontine flexure further deepens bringing the mesencephalon (midbrain) closer to the primordium of the cerebellum (metencephalon); anterior aspects of the myelincephalon (brain stem) fold underneath developing the cerebellum plate &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;7605067&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;&lt;br /&gt;
Further development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The regulation of patterning involved when he primary fissure deepens by the end of the third month and divides the vermis shows to be particularly important for development. The two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. The flocculonodular lobe is separated from another crucial part of the cerebellum, corpus cerebelli, by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The cerebellum has a very basic structure consisting 2 principal classes of neurons and 3 layers, the first is a single layer of inhibitory Purkinje cells which are sandwiched between a dense layer of excitatory granule cells, and another molecular layer of granular cell axons and purkinje cell dendritic fibres. The granule cells receive inputs from outside the cerebellum and project these inputs to purkinje cells where the majority of these inputs are further projected to a variety of cerebellar nuclei in the white matter &amp;lt;ref&amp;gt;&amp;lt;pubmed&amp;gt;25336734&amp;lt;/pubmed&amp;gt;&amp;lt;/ref&amp;gt;.&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&amp;lt;ref name=&amp;quot;PMID2775156&amp;quot;&amp;gt;&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
{| border=&amp;quot;0&amp;quot;&lt;br /&gt;
|-bgcolor=&amp;quot;CEDFF2&amp;quot; &lt;br /&gt;
| width=&amp;quot;300&amp;quot; |&amp;lt;center&amp;gt;'''Stage'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Development''' &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Historical Discoveries'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;600&amp;quot; |&amp;lt;center&amp;gt;'''Images'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Embryonic (weeks 4-5)'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''Weeks 5-6)'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; | &lt;br /&gt;
| width=&amp;quot;65&amp;quot; | &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; about &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-bgcolor=&amp;quot;F5FAFF&amp;quot; &lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; about &amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| width=&amp;quot;40&amp;quot; |&amp;lt;center&amp;gt;'''weeks'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; about&amp;lt;/center&amp;gt;&lt;br /&gt;
| width=&amp;quot;65&amp;quot; |&amp;lt;center&amp;gt; history &amp;lt;/center&amp;gt;&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
- Mechanical Movement of Neurones from Metencephalon&lt;br /&gt;
&lt;br /&gt;
- Number of Divisions Determines Cell Type&lt;br /&gt;
&lt;br /&gt;
- Differentiation of Specific Neurones&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Abnormal Development=&lt;br /&gt;
z5018156&lt;br /&gt;
&lt;br /&gt;
z5076158 could be a good article to use - https://www.ncbi.nlm.nih.gov/pubmed/22108217&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303924</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303924"/>
		<updated>2017-09-07T06:49:11Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: &lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
===Purkinje/Pyramidal Cells===&lt;br /&gt;
Discovered by Jan Evangelista Purkinje in 1837, purkinje cells are inhibitory neurons found in the outside layer of the cerebellum.  They receive signals from the granule cell parallel fibers and the superior olive and send inhibitory signals to the deep nuclei in the white matter region via GABA signaling.  Purkinje cells have a large branching network of dendrites which allows them to be identified by their morphology. z5177699&lt;br /&gt;
- Cortical Layers&lt;br /&gt;
- deep nuclei&lt;br /&gt;
- granule cells&lt;br /&gt;
- other cerebellar cells&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
z5114433&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
&lt;br /&gt;
(find images of the visualiation of the foetal cerebellum)&lt;br /&gt;
&lt;br /&gt;
z5076158&lt;br /&gt;
The development of the cerebellum begins between days 40 and 45 and it arises mostly from the metencephalon however the rhombic lips also contributes. The roof plate which is derived from the dorsal part of the alar plate thickens during development to become the cerebellum. The primary fissure deepens by the end of the third month and divides the vermis, which is the midline portion of the alar plate??, and two lateral bulges are separated into the cranial anterior lob and caudal middle lobe. As the lobes divide further into lobules, fissures are formed and this continues throughout embryonic, fetal and postnatal life, thus increasing the surface area of the cerebellar cortex. The most primitive part of the cerebellum to form is the flocculonodular lobe, which is derived from separation of the first transverse fissure and this functions to keep connections with the vestibular system and it is also concerned with subconsciously controlling equilibrium. &lt;br /&gt;
&lt;br /&gt;
The two fundamental parts of the cerebellum are the flocculonodular lobe and the corpus cerebelli and these are separated by the posterolateral fissure. &lt;br /&gt;
&lt;br /&gt;
The nuclei from the cerebellum are formed by a complex process of neurogenesis and neuronal migration. There are two types of grey matter in the cerebellum, the deep cerebellar nuclei and an external cerebellar cortex. There are 4 deep nuclei formed and the output of the cerebellar cortex are relayed through these nuclei, the ventricular layer produces 4 types of neurons that migrate to the cortex. &lt;br /&gt;
The adjacent rhombic lips gives rise to cerebellar granule cells. &lt;br /&gt;
[https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-150-the-brainstem-metencephalon-fourth-vesicle-the-cerebellum]&lt;br /&gt;
&amp;lt;ref&amp;gt;Schoenwolf, G.C., Bleyl, S.B., Brauer, P.R. and Francis-West, P.H., 2014. Larsen's Human Embryology E-Book. Elsevier Health Sciences.&amp;lt;/ref&amp;gt;&lt;br /&gt;
&lt;br /&gt;
z5018156 - https://www.ncbi.nlm.nih.gov/pubmed/21295689 &lt;br /&gt;
&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
z5114433&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
- Mechanical Movement of Neurones from Metencephalon&lt;br /&gt;
&lt;br /&gt;
- Number of Divisions Determines Cell Type&lt;br /&gt;
&lt;br /&gt;
- Differentiation of Specific Neurones&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Abnormal Development=&lt;br /&gt;
z5018156&lt;br /&gt;
&lt;br /&gt;
z5076158 could be a good article to use - https://www.ncbi.nlm.nih.gov/pubmed/22108217&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
&amp;lt;references/&amp;gt;&lt;br /&gt;
https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-1333-8_9&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=303868</id>
		<title>Talk:2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=303868"/>
		<updated>2017-09-07T06:23:52Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Project Starting Places */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project discussion page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Project Starting Places=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 6 below are some starting places.&lt;br /&gt;
&lt;br /&gt;
{{Neural Links 2}}&lt;br /&gt;
&lt;br /&gt;
PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
Cerebellum: links between development, developmental disorders and motor learning; [http://journal.frontiersin.org/article/10.3389/fnana.2012.00001/full]&lt;br /&gt;
&lt;br /&gt;
Cellular commitment in the developing cerebellum [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4290586/] &lt;br /&gt;
&lt;br /&gt;
Recent papers&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed limit=5&amp;gt;Cerebellum+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the folding of the neural tubes to form the cranial and caudal region of the embryo (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
=Z5076158=&lt;br /&gt;
==Week 7 Work== &lt;br /&gt;
What I could add: Paramotal cells, molecular layer, what cerebellum connects to, how they are remodeled postnatally Kahals research&lt;br /&gt;
https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-150-the-brainstem-metencephalon-fourth-vesicle-the-cerebellum  - good reference &lt;br /&gt;
LARSONS HUMAN EMBRYOLOGY TEXTBOOK&lt;br /&gt;
The metencephalon gives rise to the pons and the cerebellum, the adjacent rhombic lips also contribute to the development of cerebellum. The pons functions to relay signals that link both the spinal cord and cerebral cortex with the cerebellum and the cerebellum is a centre for postural and balance control. Pontine nuclei relay information from cerebrum to the cerebellum. &lt;br /&gt;
The cerebellum is first recognized as a pair of thickened cerebellar plates or cerebellar primordia. &lt;br /&gt;
Adjacent rhombic lips gives rise to Cerebellar granule cells&lt;br /&gt;
Major portion of the cerebellum consists of a narrow median swelling called the vermis and this grows faster than the flocculonodular which were the primitive part of the cerebellum and therefore becomes the dominant portion of the mature cerebellum. &lt;br /&gt;
Folding: &lt;br /&gt;
Primary fissure deepens by end of third month and divides vermis and hemispheres into a cranial anterior lobe and caudal middle lobe. Lobes divide further into lobules due to development of transverse fissures. This fissure formation and foliation continues throughout embryonic, fetal and postnatal life and this is done to increase the surface area of the cerebellar cortex. &lt;br /&gt;
2 types of grey matter present: &lt;br /&gt;
- Internal deep cerebellar nucler &lt;br /&gt;
- External cerebellar cortex &lt;br /&gt;
4 deep nuclei and all output of the cerebellar cortex is relayed through these nuclei. &lt;br /&gt;
These nuclei and cortex are produced by a process called neurogenesis and neuronal migration&lt;br /&gt;
1.	Dentate&lt;br /&gt;
2.	Globose&lt;br /&gt;
3.	Emboliform&lt;br /&gt;
4.	Fastigular &lt;br /&gt;
&lt;br /&gt;
4th month – germinal layers undergo cell division and this produces populations of cerebellar neurons. &lt;br /&gt;
•	Ventricular layer – purkinje cells, golgi cells, basket cells, stellate cells&lt;br /&gt;
•	Granule cells remaining from the cerebellar cortex (these arise from external germinal layer) &lt;br /&gt;
•	External germinal layer – primitive nuclear neurons  these migrate to form deep cerebellar nuclei&lt;br /&gt;
&lt;br /&gt;
=Topic Selection=&lt;br /&gt;
Hi group! I am personally interested in the development of the heart! Also, are you guys happy to exchange details after the lab tomorrow? - z5018156&lt;br /&gt;
&lt;br /&gt;
Hi! Im happy to share details! And yeah heart would be interesting, but I was also thinking maybe the ear? that could be cool&lt;br /&gt;
&lt;br /&gt;
Hey, yeah I was thinking the heart- I did a course on it last semester, but i also feel its quite generic and the other groups would do something similar. Shall we wait until the end of prac and find each other? Call out number 6 LMAO (z5114433)&lt;br /&gt;
&lt;br /&gt;
Hey all! I'm pretty open about topics but I was leaning towards the eye? Unless that's too close to optom, (and it might be a popular subject too?) I'm fine with anything. Let's find each other after prac! -z5113034&lt;br /&gt;
&lt;br /&gt;
The ear sounds good as well as the eye, theres also the lungs as well! We can just make a list and then decide as a group! - z5018156&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=303858</id>
		<title>Talk:2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=303858"/>
		<updated>2017-09-07T06:19:45Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Project Starting Places */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project discussion page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Project Starting Places=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 6 below are some starting places.&lt;br /&gt;
&lt;br /&gt;
{{Neural Links 2}}&lt;br /&gt;
&lt;br /&gt;
PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
Cerebellum: links between development, developmental disorders and motor learning; [http://journal.frontiersin.org/article/10.3389/fnana.2012.00001/full]&lt;br /&gt;
&lt;br /&gt;
Recent papers&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed limit=5&amp;gt;Cerebellum+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the folding of the neural tubes to form the cranial and caudal region of the embryo (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
=Z5076158=&lt;br /&gt;
==Week 7 Work== &lt;br /&gt;
What I could add: Paramotal cells, molecular layer, what cerebellum connects to, how they are remodeled postnatally Kahals research&lt;br /&gt;
https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-150-the-brainstem-metencephalon-fourth-vesicle-the-cerebellum  - good reference &lt;br /&gt;
LARSONS HUMAN EMBRYOLOGY TEXTBOOK&lt;br /&gt;
The metencephalon gives rise to the pons and the cerebellum, the adjacent rhombic lips also contribute to the development of cerebellum. The pons functions to relay signals that link both the spinal cord and cerebral cortex with the cerebellum and the cerebellum is a centre for postural and balance control. Pontine nuclei relay information from cerebrum to the cerebellum. &lt;br /&gt;
The cerebellum is first recognized as a pair of thickened cerebellar plates or cerebellar primordia. &lt;br /&gt;
Adjacent rhombic lips gives rise to Cerebellar granule cells&lt;br /&gt;
Major portion of the cerebellum consists of a narrow median swelling called the vermis and this grows faster than the flocculonodular which were the primitive part of the cerebellum and therefore becomes the dominant portion of the mature cerebellum. &lt;br /&gt;
Folding: &lt;br /&gt;
Primary fissure deepens by end of third month and divides vermis and hemispheres into a cranial anterior lobe and caudal middle lobe. Lobes divide further into lobules due to development of transverse fissures. This fissure formation and foliation continues throughout embryonic, fetal and postnatal life and this is done to increase the surface area of the cerebellar cortex. &lt;br /&gt;
2 types of grey matter present: &lt;br /&gt;
- Internal deep cerebellar nucler &lt;br /&gt;
- External cerebellar cortex &lt;br /&gt;
4 deep nuclei and all output of the cerebellar cortex is relayed through these nuclei. &lt;br /&gt;
These nuclei and cortex are produced by a process called neurogenesis and neuronal migration&lt;br /&gt;
1.	Dentate&lt;br /&gt;
2.	Globose&lt;br /&gt;
3.	Emboliform&lt;br /&gt;
4.	Fastigular &lt;br /&gt;
&lt;br /&gt;
4th month – germinal layers undergo cell division and this produces populations of cerebellar neurons. &lt;br /&gt;
•	Ventricular layer – purkinje cells, golgi cells, basket cells, stellate cells&lt;br /&gt;
•	Granule cells remaining from the cerebellar cortex (these arise from external germinal layer) &lt;br /&gt;
•	External germinal layer – primitive nuclear neurons  these migrate to form deep cerebellar nuclei&lt;br /&gt;
&lt;br /&gt;
=Topic Selection=&lt;br /&gt;
Hi group! I am personally interested in the development of the heart! Also, are you guys happy to exchange details after the lab tomorrow? - z5018156&lt;br /&gt;
&lt;br /&gt;
Hi! Im happy to share details! And yeah heart would be interesting, but I was also thinking maybe the ear? that could be cool&lt;br /&gt;
&lt;br /&gt;
Hey, yeah I was thinking the heart- I did a course on it last semester, but i also feel its quite generic and the other groups would do something similar. Shall we wait until the end of prac and find each other? Call out number 6 LMAO (z5114433)&lt;br /&gt;
&lt;br /&gt;
Hey all! I'm pretty open about topics but I was leaning towards the eye? Unless that's too close to optom, (and it might be a popular subject too?) I'm fine with anything. Let's find each other after prac! -z5113034&lt;br /&gt;
&lt;br /&gt;
The ear sounds good as well as the eye, theres also the lungs as well! We can just make a list and then decide as a group! - z5018156&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=303856</id>
		<title>Talk:2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=Talk:2017_Group_Project_6&amp;diff=303856"/>
		<updated>2017-09-07T06:19:05Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Project Starting Places */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017discussion}}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project discussion page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Project Starting Places=&lt;br /&gt;
[[User:Z8600021|Mark Hill]] ([[User talk:Z8600021|talk]]) 10:15, 14 August 2017 (AEST) OK Group 6 below are some starting places.&lt;br /&gt;
&lt;br /&gt;
{{Neural Links 2}}&lt;br /&gt;
&lt;br /&gt;
PubMed Searches: [http://www.ncbi.nlm.nih.gov/pubmed?term=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
BMC Dev Biol Search: [http://www.biomedcentral.com/bmcdevbiol/search/results?terms=Cerebellum+Development ''Cerebellum Development'']&lt;br /&gt;
&lt;br /&gt;
http://journal.frontiersin.org/article/10.3389/fnana.2012.00001/full&lt;br /&gt;
&lt;br /&gt;
Recent papers&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed limit=5&amp;gt;Cerebellum+Development&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the folding of the neural tubes to form the cranial and caudal region of the embryo (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
=Z5076158=&lt;br /&gt;
==Week 7 Work== &lt;br /&gt;
What I could add: Paramotal cells, molecular layer, what cerebellum connects to, how they are remodeled postnatally Kahals research&lt;br /&gt;
https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-150-the-brainstem-metencephalon-fourth-vesicle-the-cerebellum  - good reference &lt;br /&gt;
LARSONS HUMAN EMBRYOLOGY TEXTBOOK&lt;br /&gt;
The metencephalon gives rise to the pons and the cerebellum, the adjacent rhombic lips also contribute to the development of cerebellum. The pons functions to relay signals that link both the spinal cord and cerebral cortex with the cerebellum and the cerebellum is a centre for postural and balance control. Pontine nuclei relay information from cerebrum to the cerebellum. &lt;br /&gt;
The cerebellum is first recognized as a pair of thickened cerebellar plates or cerebellar primordia. &lt;br /&gt;
Adjacent rhombic lips gives rise to Cerebellar granule cells&lt;br /&gt;
Major portion of the cerebellum consists of a narrow median swelling called the vermis and this grows faster than the flocculonodular which were the primitive part of the cerebellum and therefore becomes the dominant portion of the mature cerebellum. &lt;br /&gt;
Folding: &lt;br /&gt;
Primary fissure deepens by end of third month and divides vermis and hemispheres into a cranial anterior lobe and caudal middle lobe. Lobes divide further into lobules due to development of transverse fissures. This fissure formation and foliation continues throughout embryonic, fetal and postnatal life and this is done to increase the surface area of the cerebellar cortex. &lt;br /&gt;
2 types of grey matter present: &lt;br /&gt;
- Internal deep cerebellar nucler &lt;br /&gt;
- External cerebellar cortex &lt;br /&gt;
4 deep nuclei and all output of the cerebellar cortex is relayed through these nuclei. &lt;br /&gt;
These nuclei and cortex are produced by a process called neurogenesis and neuronal migration&lt;br /&gt;
1.	Dentate&lt;br /&gt;
2.	Globose&lt;br /&gt;
3.	Emboliform&lt;br /&gt;
4.	Fastigular &lt;br /&gt;
&lt;br /&gt;
4th month – germinal layers undergo cell division and this produces populations of cerebellar neurons. &lt;br /&gt;
•	Ventricular layer – purkinje cells, golgi cells, basket cells, stellate cells&lt;br /&gt;
•	Granule cells remaining from the cerebellar cortex (these arise from external germinal layer) &lt;br /&gt;
•	External germinal layer – primitive nuclear neurons  these migrate to form deep cerebellar nuclei&lt;br /&gt;
&lt;br /&gt;
=Topic Selection=&lt;br /&gt;
Hi group! I am personally interested in the development of the heart! Also, are you guys happy to exchange details after the lab tomorrow? - z5018156&lt;br /&gt;
&lt;br /&gt;
Hi! Im happy to share details! And yeah heart would be interesting, but I was also thinking maybe the ear? that could be cool&lt;br /&gt;
&lt;br /&gt;
Hey, yeah I was thinking the heart- I did a course on it last semester, but i also feel its quite generic and the other groups would do something similar. Shall we wait until the end of prac and find each other? Call out number 6 LMAO (z5114433)&lt;br /&gt;
&lt;br /&gt;
Hey all! I'm pretty open about topics but I was leaning towards the eye? Unless that's too close to optom, (and it might be a popular subject too?) I'm fine with anything. Let's find each other after prac! -z5113034&lt;br /&gt;
&lt;br /&gt;
The ear sounds good as well as the eye, theres also the lungs as well! We can just make a list and then decide as a group! - z5018156&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303376</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303376"/>
		<updated>2017-09-05T12:56:09Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Neurons */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
- Purkinje fibers&lt;br /&gt;
- Cortical Layers&lt;br /&gt;
- deep nuclei&lt;br /&gt;
- granule cells&lt;br /&gt;
- other cerebellar cells&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
==Neurons==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&amp;lt;pubmed&amp;gt;17786810&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&amp;lt;pubmed&amp;gt;19555291&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Purkinje fibres; [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1357472/]&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
z5076158&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
==Mechanical Movement of Neurones from Metencephalon==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Number of Divisions Determines Cell Type==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Differentiation of Specific Neurones==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Visualisation of Fetal Cerebellum=&lt;br /&gt;
-Ultrasound&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
==Journals==&lt;br /&gt;
==Reviews==&lt;br /&gt;
==Articles==&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303374</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303374"/>
		<updated>2017-09-05T12:54:50Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Neurons */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
- Purkinje fibers&lt;br /&gt;
- Cortical Layers&lt;br /&gt;
- deep nuclei&lt;br /&gt;
- granule cells&lt;br /&gt;
- other cerebellar cells&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
==Neurons==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&amp;lt;pubmed&amp;gt;17786810&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
Purkinje fibres; [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1357472/]&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
z5076158&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
==Mechanical Movement of Neurones from Metencephalon==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Number of Divisions Determines Cell Type==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Differentiation of Specific Neurones==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Visualisation of Fetal Cerebellum=&lt;br /&gt;
-Ultrasound&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
==Journals==&lt;br /&gt;
==Reviews==&lt;br /&gt;
==Articles==&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303372</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303372"/>
		<updated>2017-09-05T12:54:26Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Neurons */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
- Purkinje fibers&lt;br /&gt;
- Cortical Layers&lt;br /&gt;
- deep nuclei&lt;br /&gt;
- granule cells&lt;br /&gt;
- other cerebellar cells&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
==Neurons==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&amp;lt;pubmed&amp;gt;17786810&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1357472/]&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
z5076158&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
==Mechanical Movement of Neurones from Metencephalon==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Number of Divisions Determines Cell Type==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Differentiation of Specific Neurones==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Visualisation of Fetal Cerebellum=&lt;br /&gt;
-Ultrasound&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
==Journals==&lt;br /&gt;
==Reviews==&lt;br /&gt;
==Articles==&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303370</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303370"/>
		<updated>2017-09-05T12:51:39Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Neurons */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
- Purkinje fibers&lt;br /&gt;
- Cortical Layers&lt;br /&gt;
- deep nuclei&lt;br /&gt;
- granule cells&lt;br /&gt;
- other cerebellar cells&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
==Neurons==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&amp;lt;pubmed&amp;gt;17786810&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
z5076158&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
==Mechanical Movement of Neurones from Metencephalon==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Number of Divisions Determines Cell Type==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Differentiation of Specific Neurones==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Visualisation of Fetal Cerebellum=&lt;br /&gt;
-Ultrasound&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
==Journals==&lt;br /&gt;
==Reviews==&lt;br /&gt;
==Articles==&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303368</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303368"/>
		<updated>2017-09-05T12:48:43Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Neurons */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
- Purkinje fibers&lt;br /&gt;
- Cortical Layers&lt;br /&gt;
- deep nuclei&lt;br /&gt;
- granule cells&lt;br /&gt;
- other cerebellar cells&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
==Neurons==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
&amp;lt;pubmed&amp;gt;21309081&amp;lt;/pubmed&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
z5076158&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
==Mechanical Movement of Neurones from Metencephalon==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Number of Divisions Determines Cell Type==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Differentiation of Specific Neurones==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Visualisation of Fetal Cerebellum=&lt;br /&gt;
-Ultrasound&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
==Journals==&lt;br /&gt;
==Reviews==&lt;br /&gt;
==Articles==&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
	<entry>
		<id>https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303366</id>
		<title>2017 Group Project 6</title>
		<link rel="alternate" type="text/html" href="https://embryology.med.unsw.edu.au/embryology/index.php?title=2017_Group_Project_6&amp;diff=303366"/>
		<updated>2017-09-05T12:47:26Z</updated>

		<summary type="html">&lt;p&gt;Z5113034: /* Neurons */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;{{ANAT2341Project2017header}}&lt;br /&gt;
&amp;lt;!-- Do not remove template above from the project page --&amp;gt;&lt;br /&gt;
&lt;br /&gt;
=Introduction=&lt;br /&gt;
&lt;br /&gt;
=Basic anatomy of the Cerebellum=&lt;br /&gt;
&lt;br /&gt;
==Neural Development== &lt;br /&gt;
(z5114433)&lt;br /&gt;
will fix referencing stuff later #ceebsrn&lt;br /&gt;
&lt;br /&gt;
Neural development is one of the earliest systems to begin and the last to be completed after birth due to its highly complex structure. The first step in neural development occurs at the end of week 3 and involves the neural groove fusing to form the neural tube, which then folds to form the cranial and caudal region of the embryo, and ultimately form the cerebellum (''https://discovery.lifemapsc.com/library/review-of-medical-embryology/chapter-26-embryonic-folding-and-flexion-of-the-embryo'') . There is a high chance of neural dysfunction and defects during the fetal neural development particularly due to the long development time frame and the need of certain nutrients such as folic acid to successfully close the tubes. Neural tube defects (NTDs) such as [[spina bifida]] and [[anencephaly]] can arise if the tubes do not close effectively.&lt;br /&gt;
&lt;br /&gt;
==Microanatomy== &lt;br /&gt;
- Purkinje fibers&lt;br /&gt;
- Cortical Layers&lt;br /&gt;
- deep nuclei&lt;br /&gt;
- granule cells&lt;br /&gt;
- other cerebellar cells&lt;br /&gt;
&lt;br /&gt;
==Early Brain Structure==&lt;br /&gt;
- primary&lt;br /&gt;
- secondary&lt;br /&gt;
- ventricles &lt;br /&gt;
&lt;br /&gt;
==Metencephalon==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Blood Supply==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
==Meninges==&lt;br /&gt;
(z5114433)&lt;br /&gt;
&lt;br /&gt;
==Neurons==&lt;br /&gt;
z5113034&lt;br /&gt;
&lt;br /&gt;
[https://www.ncbi.nlm.nih.gov/pubmed/21309081 &amp;quot;[1]&amp;quot;]&lt;br /&gt;
&lt;br /&gt;
=Cerebellum Development=&lt;br /&gt;
z5076158&lt;br /&gt;
==Cerebellum Development Stages==&lt;br /&gt;
&lt;br /&gt;
==Embryonic Cerebellum Development==&lt;br /&gt;
&lt;br /&gt;
==Fetal Cerebellum Development&lt;br /&gt;
&lt;br /&gt;
==Third Trimester==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Developmental signalling processes=&lt;br /&gt;
&lt;br /&gt;
==Mechanical Movement of Neurones from Metencephalon==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Number of Divisions Determines Cell Type==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
==Differentiation of Specific Neurones==&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
=Visualisation of Fetal Cerebellum=&lt;br /&gt;
-Ultrasound&lt;br /&gt;
&lt;br /&gt;
=Historic Images=&lt;br /&gt;
&lt;br /&gt;
=Abnormalities=&lt;br /&gt;
&lt;br /&gt;
=References=&lt;br /&gt;
==Journals==&lt;br /&gt;
==Reviews==&lt;br /&gt;
==Articles==&lt;br /&gt;
&lt;br /&gt;
=Terms=&lt;/div&gt;</summary>
		<author><name>Z5113034</name></author>
	</entry>
</feed>