cerebral cortex - jullet Flashcards
What is the difference between primary cortices and association cortices?
PRIMARY = receive specific sensory input and provide limb/eye movements. ASSOCIATION = combine input from multiple primary cortical areas and participate in complex cortical functions
What is the difference between the neocortex and the allocortex?
NEOCORTEX: outer layer of the cerebral cortex, with 6 layers. ALLOCORTEX: regions of the cerebral cortex that has fewer celll layers than the neocortex
What is the allocortex subdivided into:
paleocortex (olfactory cortex) and archicortex (hippocampus)
What is layer I of the neocortex called?
molecular layer
What is layer II of the neocortex called?
external granular layer
What is layer III of the neocortex called?
external pyramidal layer
What is layer IV of the neocortex called?
internal granular layer
What is layer V of the neocortex called?
internal pyramidal layer
What is layer VI of the neocortex called?
multi-form/fusiform layer
Which layer(s) of the neocortex project out of the cortex?
layers V, VI
What is the supragranular layer?
layers I-III of the cerebral cortex; primary origin and termination of INTRAcortical connections (associational or commissural)
The intracortical connections of the supragranular layers of the cortex can either be associational or commissural. What does this mean?
ASSOCIATIONAL: connections with areas of the SAME hemisphere. COMMISSURAL: connections with the contralateral hemisphere (ie corpus callosum, anterior commissure)
What are association fibers? Where do they arise and terminate?
white matter fibers that connect one part of the cortex to another in the same hemisphere. ARISE: pyramidal neurons in layers 3 and 5 and terminates in layers 1, 2, 3
What are commissural fibers? Where do they arise and terminate?
connect one hemisphere to another (ie corpus callosum, anterior commissure)
What is the internal granular layer?
layer IV of the cerebral cortex, receives thalamocortical input, especially from thalamic nuclei. Most prominent in primary sensory areas. Least prominent in motor areas (= agranular cortex)
Where is the internal granular layer most prominent? Least?
layers IV, most prominent in primary sensory areas. Least prominent in motor areas (= agranular cortex)
What is the infragranular layer?
layers V-VI; connect cerebral cortex with subcortical regions; most prominent in motor areas.
Where is the infragranular layer most prominent?
layers V-VI; most prominent in motor areas.
Where does layer 5 of the infragranular layer project to?
basal ganglia, brainstem, spinal cord
Where does layer 6 of the infragranular layer project to?
thalamus
What are the 3 neuronal cell types in the neocortex?
1) spiny stellate, 2) pyramidal, 3) non-pyramidal/interneurons.
What type of neurotransmitters do the neuronal cell types in the neocortex release? (remember there are 3 major cell types, but 2 major neurotransmitters)
GLUTAMATE = spiny stellate and pyramidal. GABA = non-pyramidal/interneurons
What type of cells are present in layer I of the neocortex?
mostly inhibitory (GABAergic) neurons and axons/dendrites of excitatory neurons from the deep cortical layers
What type of cells are present in layer IV of the neocortex?
spiny stellate cells - receive thalamocortical input as well as input from other cortical cells. Output results from the integration of these two inputs
What type of cells are present in layers V, VI of the neocortex?
excitatory (glutamatergic) and inhibitory (GABAergic) neurons
Where are spiny stellate neurons primarily found?
layer IV
Where are pyramidal neurons primarily found?
layers 2, 3, 5, 6
What is the basic structure of pyramidal neurons? What is the functional purpose of these 3 structures?
1) prominent apical dendrite that extends into layer I, 2) numerous basal dendrites that branch laterally from the base of the cell body, and 3) axon from base of cell body. FUNCTIONAL PURPOSE: allows pyramidal neurons to receive and integrate information arriving simultaneously from multiple input pathways as well as connect to other other neurons, cortical areas (contralateral hemisphere), and subcortical areas (brainstem/spinal cord)