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19 Cards in this Set
- Front
- Back
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DETERMINANTS OF CORTICAL NEURONS |
Morphology Laminar position Molecular markers Projection patterns |
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CORTICAL PROJECTION PATTERNS |
Corticofugal: (outside cortex) - deep layers /Corticothalamic - to thalamus VI /subcerebellar - beyond thalamus SC, pons and superior colliculus
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CORTICAL PROJECTION NEURONS |
CALLOSAL - connect two hemisphere of CC via corpus callosum (CONTRALATERAL) Ipsi - same side Columnar - local connectivity
Corticocortical: (within cortex, project through midline to contralateral hemisphere) LOCAL PROJECTIONS /Columnar - IV /CALLOSAL AND IPSILATERAL (LAYERS 2-3) |
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DENDRITE MORPHOLOGY CLASSES OF EXCITATORY NEURONS |
Intratelencephalic pyramidal tract neurons corticothalamic |
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LAYERS |
Layer 1 No pyramidal neurons and few soma. Dense in dendrites and projections. Layer 2 +3 Pyramidal neurons grouped together. Layer 2 has smallest somas. Layer 3 Has pyramidal neurons whos somas are largest at lower surface and decrease in size on ascension |
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LAYERS II |
Layer IV Have pyramidal neurons and spiny stellate neurons. Densest layers - most CBs Layer V Largest pyramidal neuron somas. Largest near bottom. Sparsely packed somas vs layer 6 Layer VI Densely packed soma |
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UL VS LL |
/UL has smaller soma size vs LL /LL - more complex and elaborate dendritic treez (morphology) Connectivity UL innervate NC and striatum LL innervate subcerebral and subcortical regions. Give rise to associational and commisual Genes UL CDP, cux2 LL fezf2, otx1 |
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SPECIFICATION OF NC |
/Emx2 Pax6 / Foxg1- /Lhx2 |
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SOX5 |
Controls sequential generation of corticofugal neuronal subtypes. KO: PROBLEMS WITH LL EXPRESSION IN CORTICOFUGAL PN Axonal tracing. Retrograde transport. Subcerebral - both Callosal - contra |
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SOX 5 KO |
Only corticofugal PN affected Cux 2(UL) not affected. Fexf2 was.
B11.5: misplaced and express L5 markers. Morphology alteration. Subplate cells misplaced, pyramidal and express CTIP2 (acquire characteristics of layer V prematurely) Usually CTIP2 confined to lower region but in KO spread all over cortex |
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SOX5 MISEXPRESSION IN UL |
Generates neurons that send axons through striatum. Subcerebral projections neurons accelerated. CHANGE PROJECTION PATTERN |
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FEZF2 - CORTISPINAL PROJECTION NEURONS |
Expressed in subcerebral PN. KO- CORTISPINAL PN MISSING. LACK CSMN. CTIP2 MISSING. NOT IN LAYER V. |
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MATURATION LAYER VI IMPAIRED IN FEZF2 MUTANT |
Low levels CTIP2. POSITIVE TBR1. SIGNAL MATURATION LOST. V1 USUALLY COEXPRESS THE TWO. LAYER 6 THICKNESS INCREASE. DISORGANISED SP. |
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UL DEVELOP NORMALLY IN FEZF2-/- |
Layer V gone. |
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LAYER IV NEURONS EXPRESS LAYER V MARKERS AFTER FORCED FEZF2 EXPRESSION |
ER81. Increased expression of L5 MARKERS. /Some project subcerebrally after forced expression of fezf2. +pyramidal +apical dendrites /ULN express DLN change morphology and pattern projection /reach cortical surface and extend tangentially LONG AXON PROJECT TO STRIATUM INDUCE CS fate on own |
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SATB2 - REGULATE identity of callosally projecting neurons |
Expressed in subset of neurons in layers 2-5. KO: PROJECT SUBCEREBRAL NO LONGER VIA CORPUS CALLOSUM PROJECT THROUGH IC AND EXTN CAPSULE (REDISTRIBUTION) CHANGE PROJECTION PATTERNS OF B-GALACTOSIDASE |
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SATB2 |
Wt: CC, AC, IC/CP Ko: AC, IC/CP NO CC |
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UL IN SATB2 KO |
CTIP2 expression in UL increases. Tbr normal Cuz2 normal but mashed migration |
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LACK OF SATB2 |
Disappearance of CS TRACT BEYOND CEREBRAL PEDUNCLE. SATB2 ROLE IN MATURATION of CS PN. No alkaline phosphatase in BS PYRAMIDAL DECUSSATION MASHED |
