Module 2 Neurobiology and Development Flashcards
neural tube closure points
- Hindbrain neuropore
- Anterior neuropore (anencephaly)
- Posterior neuropore (Spina bifida)
convergent extension
extension of the embryo
Wnt activation of the planar cell polarity (PCP) pathway, Rho GTPases
folic acid
involved in:
- psychiatric/mood through TH
- Ado-Met major methyl donor for epigenetics, protein and lipid methylation
- nucleotide synthesis (purine synthesis, pyramidine reclamation)
- cell proliferation
mouse models of NTDs
crooked tail (Wnt signaling through LRP6) loop tail (convergent extension defects)
body plan (drosophila)
maternal effect genes (establishes polarity), gap genes, pair-rule genes, segmentation genes, homeotic genes (identity)
dorsal-ventral gradient
sonic hedgehog from floor plate, BMP from roof plate
microcephaly
altered balance between proliferation and apoptosis
cell cycle:
-G1-cyclin D1/D2/D3 regulation of length of G1, longer G1=more likely to leave and become neuron
-G2-M: genes target ATR/PCNT related to centrosome (downstream of RhoA)
interkinetic nuclear migration
progenitor cells only divide at the vz surface because that’s where the centrosome is, they’re anchored to the vz surface so the nucleus moves down to the centrosome when in the M phase
- otherwise microcephaly
- neurons born together migrate to the same layer
symmetric proliferation
amplify stem cells to make large progenitor pool, expansion of surface
asymmetric proliferation
neurogenesis, radial glial cells start to make both neurons and progenitors
gliogenesis
birth of astrocytes and oligodendrocytes, happens last, migrate along radial glia fibers
migration patterns
radial migration (excitatory-from vz zone of local cortex), tangential migration (inhibitory-from CGE/MGE), rostral migration (to olfactory bulb, no radial glia, slide along axons)
somatic translocation
leading process grabs onto the pial surface and pulls cell body, happens after locomotion
locomotion
glia-guided migration (dominant form of migration in cortex)
- centrosome moves forward
- nucleus moves forward (surrounded by microtubules that the centrosome pulls forward)
laminar strucure
the 6 layers in the cortex, develop “inside-out” where the deep layers are formed first then later born neurons stack on top. correlation between birth date and function (early=more cortical-subcortical projections, late=cortical-cortical projections)
functional columns
orthagonal organization, microcircuitry between superficial and deep layers in the columns. repetitive columns process defined input for specialized function
name them transcription factors
pax6 (excitatory cortex), nkx2.1 (inhibitory cortex), atoh1 (excitatory rhombic lip), ascl1/nestin (inhibitory, cerebellar vz), Otx2 (forebrain and midbrain), Gbx2 (hindbrain and spinal cord), En1 (midbrain and rhombomere 1), hox genes (rhombomeres)
(inducible) fate mapping
promoter for cell-type specific expression of cre with lsl-lacz, gets spatial lineage. if cre-ert2 then also temporal specificity
isthmic organizer
sets up compartment border, main one is fgf8. splits up otx2 and gbx2 expression to separate hindbrain from midbrain. fgf8 also found in other regions but that’s the main one. gradient of fgf8 leads to differentiation between superior and inferior colliculus