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
What directions do the axons of Layers I & II project? What is the functional implication?
Horizontal axonal projections result in integration
What direction do the axons of the Layer III project?
External pyramidal layer= Output
What direction do the axons of the Layer IV project?
Internal granular layer= Input
What direction do the axons of the Layer V project?
Internal pyramidal layer= Output
What direction do the axons of the Layer VI project?
Mulitform/fusiform layer= Output
What cortical layers is expanded in the Primary Motor Cortex?
Layer III & Layer V i.e. output layers
- External Pyramidal Layer
- Internal Pyramidal Layer
What cortical layers are expanded in the Primary Sensory Cortex?
Layer II & IV= Input
- Internal Granular Layer= Layer II
What are Brodmann’s areas based on?
Cytoarchitecture of the gray matter
What Brodmann area is the Primary Motor Cortex?
Brodmann 4
What Brodmann area is the Premotor Cortex?
Brodmann 6
What Brodmann area is the Frontal Eye Field?
Brodmann 6
Where is Broca’s Area?
Brodmann 45
**In the region of the triangular & opercular gyri of the lateral frontal lobe
What does a lesion to Broca’s Area result in?
Inability to speak–comprehension is maintained
What Brodmann area is the Somatosensory Cortex?
Brodmann 3,1,2
What Brodmann area is the Somatosensory Association Cortex?
Brodmann 5 & 7
What Brodmann area is the Primary Visual Cortex?
Brodmann 17
What Brodmann area is the Visual Association Cortex?
Brodmann 18 & 19
What Brodmann area is the Primary Auditory Cortex?
Brodmann 41
*****Note that this is in the area of the superior temporal gyrus
What Brodmann area is the Auditory Association Cortex?
Brodmann 42
What Brodmann area is the Wernicke’s Area?
Brodmann 22
What does a lesion to Wernicke’s Area result in?
Intact speech without comprehension
What Brodmann area is the Cingulate Gyrus?
Brodmann 24
What was the main cortical structure damaged in the famous Phineas Gage case? What did this result in?
Cingulate Gyrus– Brodmann 24
**Cingulate Gyrus= limbic system–resulted in drastic change in personality
What is apraxia?
Impairment in the performance of learned motor movements
What is agnosia?
Inability to process sensory information
What are the major functions of the left hemisphere?
Language
Math
What are the major functions of the right hemisphere?
Creativity
Intuition
What is melodic intonation therapy?
Therapeutic process used by music therapists and speech-language pathologists to help patients with communication disorders caused by damage to the LEFT hemisphere of the brain.
*****Speech= LEFT, Song= RIGHT
