lec 10. CNS migration

Question 1

radial migration part 1

Answer 1

neuroepithelia divide at he apical surface in radial glial cells which divide into radial glial and neuronal precursor which moves radially

Question 2

radial migration part 2

Answer 2

newborn neurons accumulate in the mantle layer, the newest ones occupying the most superficial layer.

Question 3

tangential migration

Answer 3

neurons migrate up (in spinal cord and brain) which is important for bringing in inhibitory interneurons from the subpallium to the cortex and other developing areas

Question 4

lissencephaly

Answer 4

caused by a mutation in microtubules (TUBA1A, TUBB2B, LIS1, DLX) which causes a failure of radial migration, and the preplate fails to separate. and by mutations in reelin

Question 5

reelin function

Answer 5

reelin is a large ECM protein expressed by cajal cells in the marginal zone that tells migrating cells when to stop

also expressed by granule neurons in the cerebellum

Question 6

reelin mutant

Answer 6

• preplate fails to separate
• disruption to RELN causes disruption of purkinje cell layer and in humans causes cerebellar hypoplasia
• mutation in reelin receptor (VLDLR) leads to cortical and cerebellar disruptions

Question 7

preplate

Answer 7

made up of cajal retzius cells and subplate neurons which are the earliest post-mitotic cells

Question 8

cortical plate

Answer 8

consists of later migrating neurons and exists in between Cajal cells and subplate neurons, and is where the major layers of the cortex form

Question 9

adult neural stem cells and where they are found

Answer 9

begin as radial glial cells which become astrocyte-like. they are found in the SVZ of the 4th ventricle and denate gyrus of the hippocampus

Question 10

3 types of inhibitory interneurons and where they migrate

Answer 10

gaba-ergic in cortex
dopaminergic in olfactory bulb
cholinergic in striatum

Question 11

rhombic lip cells

Answer 11

similar to neural crest cells (they are proliferative, their daughters are migratory)

Question 12

anterior rhombic lip cells

Answer 12

tangentially migrate to form the External Germinal Layer of the cerebellum which differentiates into granule neurons (Shh from purkinje layer stimulates mitosis here)

Question 13

posterior rhombic lip cells

Answer 13

tangentially migrate to the ventral hindbrain (pontine nuclei and inferior olive)

Question 14

granule neuron progenitors

Answer 14

derived from the rhombic lip and proliferate in the basal surface. they migrate tangentially first and then migrate radially

Question 15

AT0H1 and knockout effect

Answer 15

regulates production of rhombic lip. knockout causes no foliation, no pontine nucleus, and no Internal Granular Layer and human cerebellar hypoplasia

Question 16

neurons born at different times have different ___ because ____

Answer 16

fates

each layer expresses a specific set of TFs