L8 HS

Question 1

types of non radial migration ?

Answer 1

tangential and multipolar

Question 2

where do the youngest cells end up after corticogenesis ?

Answer 2

most superficial layer

Question 3

which type of migration contributes to laminar cortex ?

Answer 3

radial migration - glial guided / somal translocation

Question 4

what happens to the preplate ?

Answer 4

it seperates and the RGC migrate

Question 5

perpendicular metaphase = which division ?

Answer 5

symmeteric

Question 6

parallel metaphase = which division ?

Answer 6

asymmeteric

Question 7

whats is initially formed in inside-out migration ?

Answer 7

basal and apical dendrites of cortical neurons and then dendrites of stellate neurons in cortical plate

Question 8

axons that innervate the thalamus which form the corticothalamic tract, originate largely from ?

Answer 8

subplate and L6

Question 9

axons that project subcerebrally,
including the corticotectal, corticobulbar,
and corticospinal tracts, arise from ?

Answer 9

L5 exclusively

Question 10

Projection neurons positioned in the upper layers (L2-L4) project only within the cortex (intrahemispherically or
contralaterally. Examples ?

Answer 10

corpus callosum

Short association fibers

Question 11

cerebellar layers ?

Answer 11

molecular layer, purkinje cell, granule cell layer

Question 12

how is the cerebellar cortex formed ?

Answer 12

IKNM of RGC and migration to the mantle and marginal zone
tangential migration from VZ
Inside-out (purkinje) Outside in (granular cells)

Question 13

what does the cerebellum develop from ?

Answer 13

the rhombic lip which is a posterior section of the metencephalon

it extends posteriorly from the roof of the 4th ventricle

Question 14

in the 2nd month of cerebellar cortex development what is formed ?

Answer 14

Cranial regions of rhombic lip form ventricular

layer, mantle layer, marginal zone

Question 15

in the 3rd month of cerebellar cortex development what is formed?

Answer 15

Neuroblast proliferation in internal germinal layer
(IGL) of ventricular zone and in novel external
germinal layer (EGL)

Neuroblasts in IGL migrate outward/stay in place
Neuroblasts in EGL migrate inward/stay in place

Question 16

IGL of cerebellum produces ?

Answer 16

purkinje cells and cerebellar nuclei

purkinje cells migrate outwards (radial locomotion) along Bergmann glia

Question 17

how does the EGL in cerebellum develop ?

Answer 17

tangential migration of progenitor cells from the
ventricular epithelium of the rhombic lip.
Direction is rostrally over its surface

Question 18

what happens after purkinje cells constitute a multicellular layer beneath the external granular layer

Answer 18

proliferation in the Ventricular layer stops

Nuclear neuroblasts staying in IGL
form;
 Deep cerebellar nuclei (fastigial,
interposed, dentate)
 Ependymal cells

Question 19

following nuclei and ependymal cells formation what happens in the cerebellum ?

Answer 19

The EGL starts producing;
 Granule neuroblasts (+)
 Basket neuroblasts (-)
 Stellate neuroblasts (-)

Granule neuroblasts migrate
inward through Purkinje cell layer
to the granule cell layer

Purkinje cells are positioned into
a monolayer

Question 20

inward migration of granule cells from the EGLis what type of migration ? what cells are used to migrate

Answer 20

radial
bergmann glial fibres
leave a bifurcated axon behind (parallel fibres)

Question 21

which neural structures display non radial migration of RGC?

Answer 21

sc, basal ganglia, brainstem

Interkinetic nuclear migration and dispersion
to form marginal and intermediate zones
• Outside-in accumulation

Question 22

Tangential migration examples

Answer 22

• Migration of interneurons from the basal
  forebrain into the developing neocortex
• Migration of neurons from the SVZ to
  the olfactory bulb along the rostral
  migratory stream
• Migrations of progenitors from the
  rhombic lip to cerebellar cortex (EGL)

-Precerebellar nuclei of the brainstem

Question 23

sc at 4 weeks

Answer 23

side walls thicken
lumen slit
roof and floor plate

Question 24

sc 6 weeks - 3 months

Answer 24

rapid proliferation 3 layers

Internal or ependymal; converted
into the ependyma of the central
canal

 Intermediate or mantle; devoid of
nuclei, and later forms the
supporting framework for the
white funiculi (nerve bundle) of
spinal cord

External or marginal; future gray
column

Question 25

In the sc which neurons are formed first ?

Answer 25

somatic motor neurons then autonomic then sensory

Question 26

rostral myelenecephalon - alar plates are located where ?

Answer 26

ventrally and laterally

Question 27

In rostral myelencephalon alar and basalplates become ?

Answer 27

alar - 4 sensory/afferent tracts;
Olivary nucleus, Somatic afferent, Special and general
visceral afferent

basal - 3 motor/efferent tracts;
• Special and General visceral efferent, Somatic efferen

Question 28

caudal myelencephalon (medulla) looks like ?
alar plate forms ?
ventral part ?

Answer 28

sc
alar plate - gracile (medial)and cuneate (lateral) nuclei = Dorsal column-Medial lemniscal pathway

ventral part - corticospinal tracts

Question 29

gracile and cuneate nuc recieves info from which limbs

Answer 29

gracile - lower

cuneate - upper

Question 30

mesencephalon (midbrain)
alar plate ?
Basal plate ?

Answer 30

alar neuroblasts migrate towrads roof and form tectum
and sup/inf colliculi

basal - tegmentum - Red and Reticular Nuclei
Efferent Nuclei Substantia Nigra

Marginal white matter expands to form
Crus Cerebri
•Descending tracts from cerebral cortex to spinal cord

Question 31

how are basal ganglia generated ?

Answer 31

from ganglionic emminence in floor of telecephlon

two major subdivisions
Medial (MGE) and lateral ganglionic
eminences (LGE).