nervous system development

Question 1

how many neurons & how many connections?

Answer 1

10^11 neurons making 10^14 connections

Question 2

neural induction
(what is neural plate)

Answer 2

neural plate forms the entire CNS
ectoderm

Question 3

neural induction
(how does a cell receive neural fate)

Answer 3

BMP blocked = neural fate
(BMP = epidermal fate)

Question 4

neurulation
(steps & what molecules)

Answer 4

neural plate -> neural groove -> neural tube
via. adhesion molecules

Question 5

neural tube defects

Answer 5

can occur via fold formation / closure formation
brain / skull not form, caudal neuropore opens

Question 6

neural crest cells

Answer 6

outer edge of neural plate
migrate away when neural tube is formed to produce PNS, schwann, melanocytes, ganglia, (pns & ens)

Question 7

morphogenesis: 3 ventricle stage
(prosencephalon, mesencephalon, rhombencephalon)

Answer 7

@ rostral end of neural tube
P: forebrain
M: midbrain
R: hindbrain
(P,R: alphabetical order)

Question 8

morphogenesis: 5 ventricle stage
what do prosencephalon & rhombencephalon become

Answer 8

p -> telencephalon & diencephalon
r -> metencephalon & myelencephalon

Question 9

telencephalon fate

Answer 9

olfactory bulb, cerebral cortex, basal ganglia

Question 10

diencephalon fate

Answer 10

thalamus & hypothalamus

Question 11

metencephalon fate

Answer 11

pons & cerebellum

Question 12

myelencephalon fate

Answer 12

medulla

Question 13

patterning: roof plate
via?

Answer 13

dorsalising (interneurons)
via: BMP, FGF, Wnt

Question 14

patterning: floor plate
via?

Answer 14

ventralising (motor neurons)
via: sonic hedgehog

Question 15

brain vesicles are how thick at this stage?

Answer 15

1 cell thick (neuroepithelial cells)

Question 16

neurogenesis

Answer 16

NE cells -> radial glia -> neurons (sym, migrate) via interm progenitors & more radial glia (asym) -> astrocytes (sym)`

Question 17

neural migration

Answer 17

First wave of CP neurons arrive -> preplate splits into marginal zone & subplate
CP neurons arrange into layers (deep layers first)

Question 18

neurogenesis & gliogenesis

Answer 18

Production of neurons and glia is controlled by separate
transcriptional programs, each blocks the other
pre-birth: glia suppressed
post-birth: glia allowed

Question 19

what % are pyramidal excitatory neurons
interneurons (inhibitory)?

Answer 19

80%
20%

Question 20

axon growth
(establishing connectivity steps)

Answer 20

1. Repulsion of outgrowing axon
2. Attraction of apical dendrite
3. Elongation / retraction & branching of apical / basal dendrites
4. Activity-dependent
   spine stabilization

Question 21

axon growth
(dendritic arbor)

Answer 21

grows to meet demand

Question 22

axon growth
(growth cone - actin & microtubule, what detects?)

Answer 22

pilots path
actin: regulate shape & growth
microtubule: structural support
att/rep detected by RECEPTORS ON FILOPODIA

Question 23

synapse development
(pattern)

Answer 23

excit increases alot in prenatal then dies
inhib increases around 15 y/o

Question 24

where are excitatory synapses?

Answer 24

mostly on dendritic spines

Question 25

ocular dominance columns

Answer 25

Stripes on V.C. (layer 4) -> zebra stripe for one eye
Refined with visual experience
Interrupted b/w birth - week 6 (week ⅔ is weaker)