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Cns Migration Notes

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This is an extract of our Cns Migration document, which we sell as part of our Neuroscience 1 Notes collection written by the top tier of Oxford students.

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Discuss the role for migration in the development of the central nervous system. How can disruption of migration result in developmental disorders?
Intro
?????Migration of cells during development of CNS plays a key role in the formation of a functional CNS
?????This is because correct spatial location of neurons ensure accurate synaptic contact with neighbouring and more distant neurons
?????Mutations in the migratory process results in severe CNS disorders Cerebral cortex?

Grey matter of cerebral cortex consists of 6 neuronal layers each with a specific function o Layer 4 receives input from the thalamus o Layer 5 projects to subcortical areas Within the cortex there are both excitatory glutamatergic and inhibitory GABAergic neurons- both of these classes of neurons arise from different areas of CNS and migrate by different routes

Excitatory glutamatergic??Originate from the radial glial cells of the CNS - these cells are multipotent and have processes that attach to both the pia mater and to the ventricular surface On receiving neurogenic signals these cells undergo asymmetric division to give rise to a neuronal progenitor and another radial glia cell To show the proliferative capacity of these cells phosphohistone labelling was done and this showed a layer of dividing cells in the ventricular zone. This labelling technique also showed the presence of two additional layers which contained dividing cells: subventricular and outersubventricular layers and these contain the intermediate progenitors of the radial glia o These cells also give rise to cortical neurons and their importance is shown in Tbr2 KO models which often resulted in microcephaly in mouse models Once the excitatory neuronal progenitor is formed migration towards the pia mater occurs During the early stages of corticogenesis radial independent translocation occurs o In this process a large radial process of the neuronal progenitor which either emerges just before migration or is inherited from the radial glia cells attaches to the pial surface o Once this occurs the process of the neuronal progenitor attached to the ventricular surface detaches o This is then followed by cytoskeletal arrangements of actin in the leading process of the neuronal progenitor which causes the leading process to contract and pull the somal body towards the pia

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