nervous system development Flashcards
how many neurons & how many connections?
10^11 neurons making 10^14 connections
neural induction
(what is neural plate)
neural plate forms the entire CNS
ectoderm
neural induction
(how does a cell receive neural fate)
BMP blocked = neural fate
(BMP = epidermal fate)
neurulation
(steps & what molecules)
neural plate -> neural groove -> neural tube
via. adhesion molecules
neural tube defects
can occur via fold formation / closure formation
brain / skull not form, caudal neuropore opens
neural crest cells
outer edge of neural plate
migrate away when neural tube is formed to produce PNS, schwann, melanocytes, ganglia, (pns & ens)
morphogenesis: 3 ventricle stage
(prosencephalon, mesencephalon, rhombencephalon)
@ rostral end of neural tube
P: forebrain
M: midbrain
R: hindbrain
(P,R: alphabetical order)
morphogenesis: 5 ventricle stage
what do prosencephalon & rhombencephalon become
p -> telencephalon & diencephalon
r -> metencephalon & myelencephalon
telencephalon fate
olfactory bulb, cerebral cortex, basal ganglia
diencephalon fate
thalamus & hypothalamus
metencephalon fate
pons & cerebellum
myelencephalon fate
medulla
patterning: roof plate
via?
dorsalising (interneurons)
via: BMP, FGF, Wnt
patterning: floor plate
via?
ventralising (motor neurons)
via: sonic hedgehog
brain vesicles are how thick at this stage?
1 cell thick (neuroepithelial cells)
neurogenesis
NE cells -> radial glia -> neurons (sym, migrate) via interm progenitors & more radial glia (asym) -> astrocytes (sym)`
neural migration
First wave of CP neurons arrive -> preplate splits into marginal zone & subplate
CP neurons arrange into layers (deep layers first)
neurogenesis & gliogenesis
Production of neurons and glia is controlled by separate
transcriptional programs, each blocks the other
pre-birth: glia suppressed
post-birth: glia allowed
what % are pyramidal excitatory neurons
interneurons (inhibitory)?
80%
20%
axon growth
(establishing connectivity steps)
- Repulsion of outgrowing axon
- Attraction of apical dendrite
- Elongation / retraction & branching of apical / basal dendrites
- Activity-dependent
spine stabilization
axon growth
(dendritic arbor)
grows to meet demand
axon growth
(growth cone - actin & microtubule, what detects?)
pilots path
actin: regulate shape & growth
microtubule: structural support
att/rep detected by RECEPTORS ON FILOPODIA
synapse development
(pattern)
excit increases alot in prenatal then dies
inhib increases around 15 y/o
where are excitatory synapses?
mostly on dendritic spines
ocular dominance columns
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)
