L7 HS

Question 1

Early embryological events in the
formation of the nervous system include
a sequence of six cellular processes?

Answer 1

(1) neurogenesis (proliferation),
(2) cell
migration,
(3) cell differentiation,
4)synaptogenesis,
(5) neuronal cell death,
(6) synapse rearrangement

Question 2

what does primary neurogenesis give rise to ?

and secondary ?

Answer 2

primary - projection neurons

secondary - inter neurons

Question 3

laminar structures in brain ?

Answer 3

cortex, cerebellum and hippocampus

Question 4

what is the ventricular zone VZ?

Answer 4

epithelium lining brain vesicles in neural tube

site of primary neurogenesis

Question 5

As neurons are produced they move from the VZ to ?

Answer 5

outer surface of mantle zone increase in neural tube thickness

Question 6

types of migration ?

Answer 6

Interkinetic nuclear movement (proliferation)

Migration of cells to form neocortex (differentiation)

Question 7

Which signals mediate neuronal migration?

Answer 7

Extracellular cues
Intracellular signalling pathways
Rearrangement of cytoskeletal components

Question 8

neurons have to migrate long distnaces before they can what ?

Answer 8

differentiate

Question 9

The wall of the proencephalon-neuronal tube
structure is composed of one continuous
sheet of neuroepithelial cells of what type ?

Answer 9

pseudostratified columnar epithelium

Question 10

what are pseudostratified neuro ep cells ?

Answer 10

neural epithelium cells that are elongated bipolar cells and span the entire wall of the cerebrum

up side down orientation - apical surface near ventricle and basal near - basal lamina

Question 11

what type of migration is associated with the neural psuedostrat epithelium ?

Answer 11

inter kinetic neural migration

Question 12

nuclear movement is linked to ?

Answer 12

cell cycle

Question 13

S phase DNA synthesis occurs at ?
G2 what happens ?
G1 what happens ?

Answer 13

basal part of VZ
G2 = cells bodies move to apical part and mitosis
G1 = neuron bodies move basally

Question 14

Corticogenesis what is ?

Answer 14

neurogenesis, proliferation, differentiation and migration to form the neocortex

Inside-out migration from ventricular zone; youngest most superfical layer

Question 15

List 5 embryonic zones involved in corticogenesis

Answer 15

VZ,IZ,SP,CP,MZ
Ventricular zone 
intermediate zone
sub-plate 
cortical plate 
mantle zone 

give rise to 6 layered cortex

Question 16

what type of migration contributes to columnar organisation ?

Answer 16

radial migration and glial guided migration

Question 17

neuronal migration routes

Answer 17

radial migration - progenitor zone (VZ) towards surface of the brain following radial layout of neuronal tube
(parallel to Radial Glia)

tangental migration - non-radial) Cells migrate orthogonally to the direction of radial migration (orthogonal to RG)

Multipolar Migration (non-radia

Question 18

Radial migration involves ?

Answer 18

Glial-Guided Locomotion
Somal Translocation (glial independent)

Radial glial scaffold provides a substrate for
directed neuronal migration

The columnar organization of the mammalian
neocortex develops from the RG scaffold

Question 19

what are RGC?

Answer 19

specialized glial cells that extend long radial processes towards overlying cerebral wall

Question 20

where does the basal progenitor cells divide to give 2 neurons ?

Answer 20

sub ventricular zone

Question 21

RGCs under what type of movement ?

Answer 21

interkinetic nuclear movement in VZ

mitosis at apical VZ
S phase dna syn at basal VZ

Question 22

cortical projection neurons migrate through what three phases ?

Answer 22

gial guided locomotion
somal translocation
multipolar

Question 23

cortical interneurons migrate ?

Answer 23

tangentially along the marginal zone and intermediate zone from their origins in the basal forebrain.

later they migrate on the cortical plate

Question 24

glial guided locomotion when does it occur ?

neurons go from where to where

Answer 24

during late corticogenesis - delivers neurons from the cortical plate to the mantle and subplate

usinf RG scaffold neurons use a salatory locomotion short bursts of movement with stops

35um/h

Question 25

somal translocation when does it occur ?

neurons go from where to where

Answer 25

early corticogenesis = from VZ to pia surface

trailing process anchors neurons to VZ
leading process - lamammellipodium attaches neurons to pial
surface

leading process retraction an draws neurons to pia surface - fast 60um/h

neurons diffrin to astrocytes

Question 26

Somal translocation - interaction of which components for this movement ?

Answer 26

LIS1 and dyein with microtubules network reg leading process retraction.

Question 27

what neurons migrate tangenitally ?

Answer 27

olfactory
GABA
GnRH - nose - forebrain - hypothalamus

migration of interneurons from ganglionic emminence to cerebral cortex

Question 28

NCC migrate through which pathways ?

Answer 28

dorsally - under the skin

Ventrally - through scleratome

receive inductive signals from environment

Question 29

from ant-pos the neural axis can be divided into ?

Answer 29

cranial, vagal, trunk

and lumbrosacral levels

Question 30

how can lineage be determined ?

Answer 30

inject parent cell with dye and progeny will inherit

Question 31

How to birth date neurons ?

Answer 31

tritium-labelled thymidine autoradiography

Only cells at last/terminal division, ie postmitotic neuroblast, retain label and ”are
born” at time of injection (stain is diluted upon subsequent divisions).

OR Bromodeoxyuridine (BrDU)

Question 32

Meauring cell proliferation ?

Answer 32

fraction of labelled mitosis to determine length of cell cycle

Question 33

During cortical development which cell cycle phase is extended ?

Answer 33

G1 phase