cerebral cortex

Question 1

6 layers of neocortex

Answer 1

1 - molecular layer, few GABAergic neurons, mostly axons and dendrites of cortical neurons
2 - external granular layer
3 - external pyramidal layer (similar to 2)
4 - internal granular layer - Spiny stellate cells receive direct thalamocortical input
5 - internal pyramidal
6 - fusiform

Question 2

3 zones of neocortex

Answer 2

1 - supragranular (layers 1-3), Primary origin & termination of intracortical connections which are associational (same hemisphere) or commissural (opposite hemisphere)
2 - internal granular layer (layer 4), thalamocortical input esp. from specific thalamic nuclei, most prominent in primary sensory cortices
3 - infragranular layers (layers 5-6), Primarily connect cerebral cortex w/ subcortical regions, most developed in motor cortical areas

Question 3

where are spiny stellate neurons found?

Answer 3

layer 4 (internal granular layer) of neocortex

Question 4

what is the function of spiny stellate neurons?

Answer 4

• release glutamate as fast excitatory NT
• relay cell for thalamocortical input
• project to pyramidal cells in layers 2 and 3

Question 5

where are pyramidal neurons?

Answer 5

neocortex layers 2, 3, 5, 6

Question 6

function of pyramidal neurons?

Answer 6

• excitatory with glutamate
• neurons in 2/3 synapse with layer 5
• receive and integrate information from many pathways
• mostly project to subcortical structures from layers 5 and 6

Question 7

where are non-pyramidal inhibitory neurons found?

Answer 7

all layers of neocortex

Question 8

function of non-pyramidal inhibitory neurons?

Answer 8

• inhibit with GABA

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