Cerebral Cortex Flashcards
What is the average thickness of the gray matter of the cortex?
Where is it thickest and thinnest?
2.5mm
Range:
- 5mm at the occipital cortex
- 5mm at the primary motor cortex
What are the 3 types of cortices?
- Isocortex: 6 layers– primary sensory and motor cortex
- Mesocortex (Paleocortex, Archicortex): Intermediate– cingulate gyrus, parahippocampal cortex
- Allocortex: 3 layers– primary olfactory cortex and hippocampal formation
What is the only cortical layer without pyramidal neruons?
1
What are the types of principal neurons?
How about interneurons?
Pyramidal and Fusiform
Stellate or granule cells, Horizontal Cells of Cajal, Cells of Martinotti
What is the only excitatory interneuron?
Stellate or granule neuron– Secretes glutamate
ALL OTHERS ARE GABA SECRETING
The neurons of all six layers of the cortex develop in waves from?
When are they first recognizable?
The periventricular germinal matrix
All six layers are recognizable by 7 months of intrauterine life
What cortical layer?
- Are the stripes of Kaes-Bekhterev found
- Stripe of Gennari and band of baillarger
- Main recepient of the thalamocortical fibers
- Lowest cell packing density and location of the BEtz cells
- Internal band of Baillarger
- Cells of Martinotti are prominent here
- Layer 3 External pyramidal
- Layer 4 IN THE VISUAL CORTEX– hence the name striate cortex!
- Layer 4 Internal Granular
- Layer 5 Internal Pyramidal
- Layer 5 Internal pyramidal layer– these are form thalamic sensory nuclei thus the band IS MOST PROMINENT IN PRIMARY CORTICAL SENSORY AREAS
- Layer 6 Multiform layer
What cortical layer/s?
- Present in all types of cortex
- Present in neocortex
- Mainly receptive
- Mainly efferent
- 1 5 6
- 2 3 4
- 1 2 3 4
- 5 6
Where do these monoaminergic inputs mainly come from
- Serotonergic
- Dopaminergic:
- Noradrenergic input
- Cholinergic input
- Serotonergic: Raphe nuclei in them midbrain and pons– role in pain control, sleep and emotion
- Dopaminergic: Ventral tegmental area of tsai and the substantia nigra of the mesencephalon– role in orienting behavior
- Noradrenergic input: Locus ceruleus in the rostral pons– arousal state
- Cholinergic input: Nucleus basalis of Meynert– arousal and motivation
Which association fiber is being described?
- Connects the atnerior perforated substance with the parahippocampal gyrus
- Connects the frontal lobe with the parietal occipital and temporal lobes
- Sweeps around the insula to connect the inferior frontal area (broca) with the superior temporal gyrus (wernicke)
- Connects adjacent regions of the occipital and temporal areas
- Connects the inferior frontal gyrus with the anterior temporal lobe
- Cingulate fasciculus: Connects the atnerior perforated substance with the parahippocampal gyrus
- Superior longitudinal fasciculus: Connects the frontal lobe with the parietal occipital and temporal lobes
- Arcuate fasciculus: Sweeps around the insula to connect the inferior frontal area (broca) with the superior temporal gyrus (wernicke)
- U fibers: Connects adjacent regions of the occipital and temporal areas
- Uncinate fasciculus: Connects the inferior frontal gyrus with the anterior temporal lobe
What are the commisural fiber systems?
Corpus callosum
Anterior commissure
Hippocampal commissure
Which areas of the cortex innervate the lower subnucleus of the nuclei of CN7 of the contralateral side?
How about those that go to both upper subnuclei?
- Primary motor cortex, caudal cingulate gyrus
2. Supplementary motor cortex, rostral cingulate gyrus
Which parts of the cortex subserve EMOTIONAL expresssion?
Cingulate gyrus
Identify the Brodmann area:
Post central gyrus
Precentral gyrus
Primary visual cortex
Superior temporal gyrus, auditory association area (Wernicke’s)
Heschl’s gyrus, primary auditory cortex
Pars opercularis of the inferior frontal gyrus
Pars triangularis of the inferior frontal gyrus
BOTH form the Broca’s area
Dorsal entorhinal area for olfaction, medial most temporal lobe
Insular cortex Island of Reil, frontoparietal rolandic operculum, gustatory cortex
Post central gyrus 1,2,3
Precentral gyrus 4
Primary visual cortex 17
Superior temporal gyrus, auditory association area (Wernicke’s) 22
Heschl’s gyrus, primary auditory cortex 41 42
Pars opercularis of the inferior frontal gyrus
Pars triangularis of the inferior frontal gyrus
BOTH form the Broca’s area 44 45
Dorsal entorhinal area for olfaction, medial most temporal lobe 34
Insular cortex Island of Reil, frontoparietal rolandic operculum, gustatory cortex 43
What is the most medial representation in the sensory homunculus
Anal and genital regions
Which brodmann areas are activated by different sensory stimuli?
1 both cutaneous or proprioreceptive
2 and 3a Proprioreceptive
3b cutaneous
What do lesions in the primary somatosensory association areas in the the superior parietal lobule B5 and 7 do?
Bilateral: Optic ataxia– unable to move hand toward an object that is seen
Unilateral: Neglect of the opposite side of the body
Why would a PCA infarct still have macular sparing?
Because of the collateral supply from the MCA to the macular area of the cortex