Exam #3: Cerebral Cortex Flashcards
What part of the cerebral cortex is the “new cortex?”
Neocortex
What part of the cerebral cortex is the “ ancient cortex?”
Allocortex
What structures are part of the allocortex? How many layers are there in the allocortex?
Hippocampus= 3 layers
Paleocortex
Mesocortex
What is the paleocortex? How many layers are there in the paleocortex?
Primary & secondary olfactory cortex
*****3-5
What is the mesocortex? How many layers are there in the mesocortex?
Cingulate gyrus
Insular cortex
**3-6
How do our brains compare to chimps?
- Much more neocortex in humans
**Roughly equal size of primary areas (visual, motor, sensory…etc. but LARGER ASSOCIATION areas that integrate information between the primary areas
How does the layering of the precentral gyrus change as you go posterior into the postcentral gyrus?
- Precentral gyrus/ motor cortex= agranular & thicker
- Less cortical thickness in the sulcus
- Postcentral gyrus/ sensory cortex= granular & less thick
What is the isocortex?
Same thing as neocortex
What is the difference between homo-typical & hetero-typical cortex?
Homotypical= having the same architecture/ layering
- Association areas
Heterotypical= different architecture
- Motor cortex
- Sensory cortex
What is the difference between granular & agranular? What region is agranular? What region is granular?
Granular= speckled & “salt and pepper” appearance
- Primary sensory cortex
Agranular= smoother appearance
- Primary motor cortex
How are the layers of the cerebral cortex numbered?
Layer I is at the top
What is the major cell type seen in the cerebral cortex?
Pyramidal cells
- Basal dendrites & apical dendrites in the cortical layers
- Axons leave the cortex
What are fusiform cells?
Modified granular cell
- Apical & basal dendrites
- Axon leaves the cortex and goes to the THALAMUS
What cell types are considered interneurons?
- Stellate
- Granule–makes the distinction between granular and agranular
- Basket cell
What are the characteristics of interneurons?
Axons run horizontal in the cortex
What are retzius-cajal cells?
Cell that occurs in the upper parts of the cortex
What are Cells of Martiontti?
Cells that occur in the lower cortical layers
What cells from the cortex form most of the white matter?
Pyramidal cells
What are association fibers? List the association fibers.
White matter tracts that run within the SAME hemisphere
E.g.
- Superior longitudinal fasiculus
- Unciante fasiculus
- Occiptofrontal fasiculus
What are commissural fibers? List the commissural fibers.
White matter tracts that run to the OPPOSITE hemisphere
E.g.
- Corpus callosum
- Anterior commissure
- Posterior commissure
What are projection fibers?
White matter fibers that project from the cortex to spinal cord & vice versa
E.g.
- Posterior limb of the internal capsule
- Crus cerebri
What is the major landmark for the posterior limb of the internal capulse on coronal section?
Thalamus
Name the six layers of the cortex. What cell types are associated with these layers?
I= molecular
- Cells of Cajal
II= External granular
- Granular cells
III= External pyramidal
- Pyramidal
IV= Internal granular
- Granular
V= Internal pyramidal
- Pyramidal
VI= Multiform
- Fusiform cells
Describe the shape of the pyramidal cells in the external pyramidal layer and the internal pyramidal layer.
External= small to medium sized pyramidal cells
Internal= large sized pyramidal cells
