Neural - Spinal Cord Development
|Embryology - 22 Jul 2017 Expand to Translate|
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- 1 Introduction
- 2 Some Recent Findings
- 3 Neural Development Overview
- 4 Early Brain Vesicles
- 5 Spinal Cord Regions
- 6 Embryonic Development
- 7 Fetal Development
- 8 Plexus Development
- 9 Dermatomes
- 10 Molecular
- 11 Spinal Cord Histology
- 12 Additional Images
- 13 References
- 14 Glossary Links
Neural development is one of the earliest systems to begin and the last to be completed after birth. This development generates the most complex structure within the embryo and the long time period of development means in utero insult during pregnancy may have consequences to development of the nervous system.
The early central nervous system begins as a simple neural plate that folds to form a groove then tube, open initially at each end. Failure of these opening to close contributes a major class of neural abnormalities (neural tube defects).
Within the neural tube stem cells generate the 2 major classes of cells that make the majority of the nervous system : neurons and glia. Both these classes of cells differentiate into many different types generated with highly specialized functions and shapes. This section covers the establishment of neural populations, the inductive influences of surrounding tissues and the sequential generation of neurons establishing the layered structure seen in the brain and spinal cord.
- Neural development beginnings quite early, therefore also look at notes covering Week 3- neural tube and Week 4-early nervous system.
- Development of the neural crest and sensory systems (hearing/vision/smell) are only introduced in these notes and are covered in other notes sections.
Some Recent Findings
|More recent papers|
This table shows an automated computer PubMed search using the listed sub-heading term.
References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.
Jingquan Lin, Xue Huo, Xuehong Liu "mTOR Signaling Pathway": A Potential Target of Curcumin in the Treatment of Spinal Cord Injury. Biomed Res Int: 2017, 2017;1634801 PubMed 28691015
Liqing Wang, Chao Yu, Jun Wang, Hui Zhao, Sun-On Chan The spatiotemporal relationships between chondroitin sulfate proteoglycans and terminations of calcitonin gene related peptide and parvalbumin immunoreactive afferents in the spinal cord of mouse embryos. Neurosci. Lett.: 2017; PubMed 28689049
Balázs Gloviczki, Dénes G Török, Gábor Márton, László Gál, Tamás Bodzay, Sándor Pintér, Antal Nógrádi Delayed Spinal Cord-Brachial Plexus Reconnection after C7 Ventral Root Avulsion: The Effect of Reinnervating Motoneurons Rescued by Riluzole Treatment. J. Neurotrauma: 2017; PubMed 28657487
Hassan Al-Ali, Ying Ding, Tatiana Slepak, Wei Wu, Yan Sun, Yania Martinez, Xiao-Ming Xu, V P Lemmon, J L Bixby The mTOR substrate S6 Kinase 1 (S6K1) is a negative regulator of axon regeneration and a potential drug target for Central Nervous System injury. J. Neurosci.: 2017; PubMed 28626016
Cameron Schmidt, Ellie Bryant, Joe Iwanaga, Rod J Oskouian, W Jerry Oakes, R Shane Tubbs Meningocele manqué: a comprehensive review of this enigmatic finding in occult spinal dysraphism. Childs Nerv Syst: 2017; PubMed 28620735
Neural Development Overview
Neuralation begins at the trilaminar embryo with formation of the notochord and somites, both of which underly the ectoderm and do not contribute to the nervous system, but are involved with patterning its initial formation. The central portion of the ectoderm then forms the neural plate that folds to form the neural tube, that will eventually form the entire central nervous system.
- Early developmental sequence: Epiblast - Ectoderm - Neural Plate - Neural groove and Neural Crest - Neural Tube and Neural Crest
|Neural Tube||Primary Vesicles||Secondary Vesicles||Adult Structures|
|week 3||week 4||week 5||adult|
|Prosencephalon||Telencephalon||Rhinencephalon, Amygdala, Hippocampus, Cerebrum (Cortex), Hypothalamus, Pituitary | Basal Ganglia, lateral ventricles|
|Diencephalon||Epithalamus, Thalamus, Subthalamus, Pineal, third ventricle|
|Mesencephalon||Mesencephalon||Tectum, Cerebral peduncle, Pretectum, cerebral aqueduct|
Early Brain Vesicles
In week 3, the neural plate forms and the caudal end of the neural plate remains narrow compared to the cranial end which rapidly expands.
In week 4, when the plate folds to form the neural tube, the cranial end of the tube then forms a series of enlarged cavities (vesicles) that will eventually form the brain. The caudal end of the tube forms a narrower tube of relatively the same size along its length that will eventually form the spinal cord.
|Primary Vesicles||Secondary Vesicles|
|early embryonic||late embryonic|
Direct comparison of brain growth embryonic and fetal period. Note the relative size of the spinal cord seen at the lower end of each image.
Spinal Cord Regions
The neural tube forms similar regions around the wall along its length, including the spinal cord. The floor and roof plate are specialised developmental regions, important embryonic "patterning" regions.
- Floor plate - thin wall region that overlies the notochord. Ventral patterns the spinal cord, both floor plate and notochord produce Sonic hedgehog (Shh) (see also Notochord)
- Basal plate - thick wall region lying either side of the floor floor plate. The ventral horn motor neurons develop here and extend axons out of the spinal cord to innervate developing skeletal muscle. Tracts formed by axons surround these horns and project both up and down the spinal cord.
- Alar plate - thick wall region lying either side of the roof floor plate. The sensory dorsal horn develops there and receives axons from the sensory structures outside the spinal cord. The adult horn is divided into 6 laminae (I to VI). Tracts formed by axons surround these horns and project both up and down the spinal cord.
- Roof plate - thin wall region that underlies the dorsal ectoderm epithelium. Dorsal patterns the spinal cord, the roof plate produces Bone morphogenetic proteins (BMPs). 
- Lumen - neuroepithelium lined fluid-filled space continuous with the brain ventricular system.
|Week 4||Week 8|
| Stage 13 Spinal cord cross-section (upper part of cord).
labeled image | unlabeled image
| Stage 22 Spinal cord cross-section (ventral is at bottom of image)|
labeled image | unlabeled image
|Spinal cord cross-section (upper part of cord) (Carnegie Stage 13)|
|These listed features link to zoomed views of the virtual slide with the named feature generally in the centre of the view.
Use the (-) at the top left of the screen to see where this feature is located.
|Spinal Cord Features||Other Features
- Links: Fetal Development
The conus medullaris (Latin, "medullary cone") is the tapered, lower end of the spinal cord. An ultrasound study of the position of the spinal cord conus medullaris at 18-22 weeks (20 to 24 weeks ((GA}}) showed that it ended adjacent to vertebrae L2, L2-3 vertebral space, and L3 (73/78, 93%).
The spinal nerves initially leave the spinal cord at each individual segmental levels. At various levels they then form an intersecting network of nerves, a plexus, from which mixed segmental nerves emerge.
Search PubMed: cervical plexus embryology
- Search PubMed: brachial plexus embryology
|Adult Lumbar Plexus|
- Search PubMed: lumbar plexus embryology
A dermatome represents the area of skin that is mainly supplied by a single spinal nerve. Therefore each spinal nerve can be "mapped" to a region of the external body surface and that this "map" is established before embryonic limb rotation.
Neural tube Dorsoventral Patterning by SHH BMP
Dorsoventral domains are established by opposing concentration gradients of Sonic Hedgehog (Shh) and Bone Morphogenic Protein (BMP).
- left - These regulate progenitor gene expression. The progenitor genes cross-repress each other to establish domain boundaries.
- right - Each domain will give rise to a specific cell type that expresses various post-mitotic differentiation genes.
Spinal Cord Histology
Identify gray and white matter, central canal (surrounded by ependymal cells), dorsal and ventral horns, meninges (pia, arachnoid and dura mater), subarachnoid space with dorsal and ventral rootlets, blood vessels, a motor neurone with a cell body (soma), nucleus, nucleolus, Nissl granules, an axon with axon hillock area, dendrites, glial cells (oligodendrocytes, astrocytes).
|Spinal cord (Luxol Fast Blue)|
|Spinal cord - Grey and white matter|
|Spinal cord - Grey matter|
Grey matter (HE)
Grey matter (silver)
- Spinal Cord: Overview 1 | Overview 2 | Overview animation | Grey matter | Grey matter | Grey matter | White matter | Overview unlabeled | Grey matter unlabeled 1 | Grey matter unlabeled 2 | White matter unlabeled 1 | Ependymal cells unlabeled
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|Historic Disclaimer - information about historic embryology pages|
|Embryology History | Historic Embryology Papers)|
|Filum Terminale (1919)|
| Streeter GL. Factors involved in the formation of the filum terminale. (1919) Amer. J Anat. 22:1-11.
|Human Embryology And Morphology (1921)|
| Keith, A. Human Embryology And Morphology (1921) Longmans, Green & Co.:New York.
|Anatomy of the Human Body (1918)|
| Gray, H. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918.
- Anna Kicheva, Tobias Bollenbach, Ana Ribeiro, Helena Pérez Valle, Robin Lovell-Badge, Vasso Episkopou, James Briscoe Coordination of progenitor specification and growth in mouse and chick spinal cord. Science: 2014, 345(6204);1254927 PubMed 25258086
- Elena Y Demireva, Lawrence S Shapiro, Thomas M Jessell, Niccolò Zampieri Motor neuron position and topographic order imposed by β- and γ-catenin activities. Cell: 2011, 147(3);641-52 PubMed 22036570
- Christina Pyrgaki, Paul Trainor, Anna-Katerina Hadjantonakis, Lee Niswander Dynamic imaging of mammalian neural tube closure. Dev. Biol.: 2010, 344(2);941-7 PubMed 20558153
- Leigh Wilson, Malcolm Maden The mechanisms of dorsoventral patterning in the vertebrate neural tube. Dev. Biol.: 2005, 282(1);1-13 PubMed 15936325
- Victor V Chizhikov, Kathleen J Millen Mechanisms of roof plate formation in the vertebrate CNS. Nat. Rev. Neurosci.: 2004, 5(10);808-12 PubMed 15378040
- Victor V Chizhikov, Kathleen J Millen Roof plate-dependent patterning of the vertebrate dorsal central nervous system. Dev. Biol.: 2005, 277(2);287-95 PubMed 15617675
- Yuri Perlitz, Ido Izhaki, Moshe Ben-Ami Sonographic evaluation of the fetal conus medullaris at 20 to 24 weeks' gestation. Prenat. Diagn.: 2010, 30(9);862-4 PubMed 20582935
- 26499851</pubmed>| Neural Dev.
Nicholas D E Greene, Andrew J Copp Development of the vertebrate central nervous system: formation of the neural tube. Prenat. Diagn.: 2009, 29(4);303-11 PubMed 19206138
Fausto Ulloa, Elisa Martí Wnt won the war: antagonistic role of Wnt over Shh controls dorso-ventral patterning of the vertebrate neural tube. Dev. Dyn.: 2010, 239(1);69-76 PubMed 19681160
Jeremy S Dasen, Thomas M Jessell Hox networks and the origins of motor neuron diversity. Curr. Top. Dev. Biol.: 2009, 88;169-200 PubMed 19651305
Eric Dessaud, Andrew P McMahon, James Briscoe Pattern formation in the vertebrate neural tube: a sonic hedgehog morphogen-regulated transcriptional network. Development: 2008, 135(15);2489-503 PubMed 18621990
Bradley J Molyneaux, Paola Arlotta, Jeffrey D Macklis Molecular development of corticospinal motor neuron circuitry. Novartis Found. Symp.: 2007, 288;3-15; discussion 15-20, 96-8 PubMed 18494249
O A Glenn, A J Barkovich Magnetic resonance imaging of the fetal brain and spine: an increasingly important tool in prenatal diagnosis, part 1. AJNR Am J Neuroradiol: 2006, 27(8);1604-11 PubMed 16971596
O A Glenn, J Barkovich Magnetic resonance imaging of the fetal brain and spine: an increasingly important tool in prenatal diagnosis: part 2. AJNR Am J Neuroradiol: 2006, 27(9);1807-14 PubMed 17032846
T W Sadler Embryology of neural tube development. Am J Med Genet C Semin Med Genet: 2005, 135C(1);2-8 PubMed 15806586
Marysia Placzek, James Briscoe The floor plate: multiple cells, multiple signals. Nat. Rev. Neurosci.: 2005, 6(3);230-40 PubMed 15738958
Hirotomo Saitsu, Kohei Shiota Involvement of the axially condensed tail bud mesenchyme in normal and abnormal human posterior neural tube development. Congenit Anom (Kyoto): 2008, 48(1);1-6 PubMed 18230116
- Bayer S.A and Altman J. The Spinal Cord from Gestational Week 4 to the 4th Postnatal Month CRC Press 2002 Print ISBN: 978-0-8493-1420-9 eBook ISBN: 978-1-4200-4018-0 http://www.crcnetbase.com/doi/book/10.1201/9781420040180
November 2010 search "Spinal Cord Embryology" All (7631) Review (641) Free Full Text (1562)
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