Neural - Mesencephalon Development: Difference between revisions

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* '''Otx2 and Otx1 protect diencephalon and mesencephalon from caudalization into metencephalon during early brain regionalization.'''PMID20816794 "Otx2 is expressed in each step and site of head development.  ...In rostral forebrain, neopallium, ganglionic eminences and hypothalamus in front of prethalamus develop; we propose that they become insensitive to the caudalization with the switch from the Otx2 expression under the AN enhancer to that under FM1 and FM2 enhancers. In contrast, the medial pallium requires Otx1 and Otx2 for its development later than E9.5, and the Otx2 expression in diencepalon and mesencephalon later than E9.5 is also directed by an enhancer other than FM1 and FM2 enhancers."
* '''Otx2 and Otx1 protect diencephalon and mesencephalon from caudalization into metencephalon during early brain regionalization.'''PMID20816794 "Otx2 is expressed in each step and site of head development.  ...In rostral forebrain, neopallium, ganglionic eminences and hypothalamus in front of prethalamus develop; we propose that they become insensitive to the caudalization with the switch from the Otx2 expression under the AN enhancer to that under FM1 and FM2 enhancers. In contrast, the medial pallium requires Otx1 and Otx2 for its development later than E9.5, and the Otx2 expression in diencepalon and mesencephalon later than E9.5 is also directed by an enhancer other than FM1 and FM2 enhancers."
* Organization of the human embryonic ventral mesencephalon<ref><pubmed>19825428</pubmed></ref>
* Organization of the human embryonic ventral mesencephalon<ref><pubmed>19825428</pubmed></ref> "The neurons in the ventral mesencephalon (VM) are organized into several nuclei consisting of distinct neuronal populations. These include the dopaminergic (DA) neurons of the substania nigra and ventral tegmental area, the oculomotor (OM) neurons that innervate the muscles controlling eye movement, and the reticular neurons of the red nucleus (RN) involved in motor control and coordination reviewed in Puelles (2007).  We report that BLBP and LMX1A mark the floor plate and that FOXA2 is expressed in both the floor plate and basal plate of the human VM. The proneural transcription factors NGN2 and MASH1 are expressed in the ventricular zone of the human VM within and lateral to the floor plate. The post-mitotic DA neurons express TH as well as NURR1 and PITX3. ISL1 and BRN3A can be used to detect the cells of OM and RN, respectively. We show that many key developmental control factors are expressed in a temporal and spatial manner in the human VM essentially corresponding to what has been observed in the mouse."


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Revision as of 18:41, 7 November 2010

Notice - Mark Hill
Currently this is only a template page and is being updated (this notice removed when completed).

Introduction

Stage10 sem6.jpg

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.


Neural Links: ectoderm | neural | neural crest | ventricular | sensory | Stage 22 | gliogenesis | neural fetal | Medicine Lecture - Neural | Lecture - Ectoderm | Lecture - Neural Crest | Lab - Early Neural | neural abnormalities | folic acid | iodine deficiency | Fetal Alcohol Syndrome | neural postnatal | neural examination | Histology | Historic Neural | Category:Neural

Some Recent Findings

  • Otx2 and Otx1 protect diencephalon and mesencephalon from caudalization into metencephalon during early brain regionalization.PMID20816794 "Otx2 is expressed in each step and site of head development. ...In rostral forebrain, neopallium, ganglionic eminences and hypothalamus in front of prethalamus develop; we propose that they become insensitive to the caudalization with the switch from the Otx2 expression under the AN enhancer to that under FM1 and FM2 enhancers. In contrast, the medial pallium requires Otx1 and Otx2 for its development later than E9.5, and the Otx2 expression in diencepalon and mesencephalon later than E9.5 is also directed by an enhancer other than FM1 and FM2 enhancers."
  • Organization of the human embryonic ventral mesencephalon[1] "The neurons in the ventral mesencephalon (VM) are organized into several nuclei consisting of distinct neuronal populations. These include the dopaminergic (DA) neurons of the substania nigra and ventral tegmental area, the oculomotor (OM) neurons that innervate the muscles controlling eye movement, and the reticular neurons of the red nucleus (RN) involved in motor control and coordination reviewed in Puelles (2007). We report that BLBP and LMX1A mark the floor plate and that FOXA2 is expressed in both the floor plate and basal plate of the human VM. The proneural transcription factors NGN2 and MASH1 are expressed in the ventricular zone of the human VM within and lateral to the floor plate. The post-mitotic DA neurons express TH as well as NURR1 and PITX3. ISL1 and BRN3A can be used to detect the cells of OM and RN, respectively. We show that many key developmental control factors are expressed in a temporal and spatial manner in the human VM essentially corresponding to what has been observed in the mouse."

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 Development
Neural Tube Primary Vesicles Secondary Vesicles Adult Structures
week 3 week 4 week 5 adult
neural plate
neural groove
neural tube

Brain
prosencephalon (forebrain) telencephalon Rhinencephalon, Amygdala, hippocampus, cerebrum (cortex), hypothalamus‎, pituitary | Basal Ganglia, lateral ventricles
diencephalon epithalamus, thalamus, Subthalamus, pineal, posterior commissure, pretectum, third ventricle
mesencephalon (midbrain) mesencephalon tectum, Cerebral peduncle, cerebral aqueduct, pons
rhombencephalon (hindbrain) metencephalon cerebellum
myelencephalon medulla oblongata, isthmus
spinal cord, pyramidal decussation, central canal

Primary Vesicles

CNS primary vesicles.jpg


References

  1. <pubmed>19825428</pubmed>

Reviews

<pubmed>19206138</pubmed>


Articles

Search PubMed

Search Pubmed: Mesencephalon Embryology | Mesencephalon Development |


Glossary Links

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Cite this page: Hill, M.A. (2024, March 29) Embryology Neural - Mesencephalon Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Neural_-_Mesencephalon_Development

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G