Development of cortex

From tube to laminae...
1. How does the one-cell thick neural tube turn into the multiple layered cortices of the cerebrum and cerebellum?
  1. Neural tube initially one cell thick
    1. Cells divide by nuclear translocation
      1. Marginal zone relatively cell- free
      2. Division ↑↑ after neuropores close
2. What happens if it doesn't?
  1. Developmental abnormalities
    1. Lissencephaly
    2. Smooth brain
      1. Agyria
  2. Migration abnormalities
Cerebral cortex
1. Post-mitotic cells move from ventricular zone to form preplate
  1. Cortical plate
    1. Splits PP
    2. Forms many layers of adult cotex
2. Cajal-Retzius cells in marginal zone
  1. 1st post-mitotic cells
    1. Disappear or change phenotype later
  2. Cajal-retzius cells secrete reelin
    1. 3460 amino acids, ECM-like
    2. Reeler mice
      1. Preplate forms but cortical layers malformed
      2. Parallels to lissencephaly
    3. Stops migrating cells?
      1. Unclear role
      2. Repellent / stop signal?
  3. CR development regulated by Foxg1
    1. Foxg1 -/- has extra CR cells
3. Subplate
Inside out development
1. Using 3H – thymidine to find cell birthdays
2. Cortical layers
  1. Subventricular zone appears
    1. Localised (Sanes) or widespread
    2. Also a germinal layer
  2. White matter tracts and other layers form
Guiding migration
1. Cell movement is often associated with radial glia
  1. Radial glia have astrocyte markers
  2. Most disappear after development
    1. Except bergmann glia
      Annotations:
      - What are they?
  3. Are stem cells
2. But some is tangential (e.g. cortical interneurons)
Cerebellum
1. Forms at the roof of the IVth ventricle
  1. Cortical region
    1. Cortical layers
  2. Central nuclei
    1. Deep cerebellar
  3. Roof of IVth very thin
    1. VZ is close to surface
    2. Rhombic lip cells (germinal trigone) at the superior and inferior edges of the medullary velum
      Annotations:
      - Whut?
      1. Superior rhombic lip cells form the external germinal layer
2. Forms at boundary of the mid and hindbrains
3. Development
  1. Superior rhombic lip cells form the external germinal layer
    1. VZ produces all other cell types
    2. Inferior lip produces pontine nuclei and inferior olive
  2. The EGL produces granule cells (neurons)
    1. Granule cells migrate inwardly
      1. Cerebellar mass increases as granule cells ↑↑
        Folds appear
Control of development
1. Production of rhombic lip cells is regulated by MATH-1 (transcription factor)
  1. No MATH-1 no foliation, no IGL, no pontine nuclei
  2. Pontocerebellar hypoplasia
    Annotations:
    - Find a picture and research it a bit
2. Sonic HH released from Purkinje cells stimulates mitosis in EGL
3. Reeler mice - disordered layers
  1. Reelin from EGL
  2. Other factors

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Development of cortex

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	Created by Kristi Brogden over 11 years ago