Cerebral Cortex

Question 1

What is the cerebral cortex embryologically derived from??

Answer 1

The Telencephalon

Question 2

What are the subdivisions of the cerebral cortex?

Answer 2

Archicortex (3 layers)
Paleocortex
Neocortex (6 layers)

Question 3

4 major lobes and 2 subdivisions of the cerebral cortex:

Answer 3

Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
Insular lobe 
Limbic lobe

Question 4

Which arteries supply the cerebral cortex?

Answer 4

ACA
MCA
PCA
Anterior communicating
Posterior communicating

Question 5

What is the major venous drainage of the cerebral cortex??

Answer 5

Sagittal sinus, Inferior sagittal sinus, Straight sinus, Transverse sinus, Sigmoid sinus, which drain into internal jugular veins

Question 6

What are the six cellular layers of the cortex?

Answer 6

Layer I: Molecular layer
Layer 2: External Granular layer
Layer 3: External Pyramidal layer
Layer 4: Internal Granular layer
Layer 5: Internal Pyramidal layer
Layer 6: Multiform layer

Question 7

What are the major cell types in the cerebral cortex?

Answer 7

Pyramidal cells and Non-pyramidal cells

Question 8

Areas 3, 1, 2

Answer 8

Primary somatosensory cortex

Question 9

Area 4

Answer 9

Primary motor cortex

Question 10

Area 17

Answer 10

Primary visual cortex

Question 11

Area 41 and 42

Answer 11

Primary Auditory cortex

Question 12

Areas 44 and 45

Answer 12

Motor area of speech (Broca’s); mostly dominant in L hemisphere

Question 13

Lesion of Areas 3, 1, 2 (Primary somatosensory cortex)

Answer 13

Contralateral loss of somesthetic sensation

Question 14

Lesion of Area 4 (Primary motor cortex)

Answer 14

Contralateral spastic paralysis

Question 15

Lesion of Area 17 (Primary visual cortex)

Answer 15

Contralateral hemianopia

If restricted to upper or lower banks of Calcarine fissure –> contralateral inferior or superior quadrantanopia

Question 16

Lesion of Area 41, 42 (Primary auditory cortex)

Answer 16

Bilateral lesions lead to loss of hearing

Question 17

Lesion of Area 44 and 45 (Broca’s area)

Answer 17

Dominant side (left) --> motor aphasia, Broca's aphasia, or expressive aphasia 
Non-dominant side (right) --> difficulty expressing emotional aspect of language

Question 18

Association cortical areas of the parietal lobe

Answer 18

Posterior parietal lobe: polymodal convergence
Superior parietal lobule: areas 5 and 7
Inferior parietal lobule: supramarginal gyrus (area 40) and Angular gyrus (area 39)

Question 19

Lesion of association cortical areas of parietal lobe

Answer 19

Dominant (usually left) hemisphere –> astereognosis (area 40) aphasia, alexia and agraphia (area 39)
Non-dominant (usually right) hemisphere –> spatial distortion, contralateral neglect

Question 20

Association cortical areas of the occipital lobe

Answer 20

Secondary visual cortex: area 18 or V2
Association cortical areas: V3, V4, etc
32 visual areas in primate cortex

Question 21

Lesion to association cortical areas of occipital lobe

Answer 21

A variety of visual defects

Question 22

Association cortical areas of temporal lobe

Answer 22

Wernicke’s area: posterior part of superior temporal gyrus (area 22): language comprehension (dominant on the left)

Question 23

Lesion to association cortical areas of temporal lobe

Answer 23

Wernicke’s area (dominant hemisphere) –> sensory aphasia, Wenicke’s aphasia, receptive aphasia
Wernicke’s area (non-dominant hemisphere) –> difficulty in comprehending the emotional aspect of language

Question 24

Cortico-cortical connections within the same hemisphere and between two hemispheres

Answer 24

Short association fibers
Long association fibers
Callosal fibers

Question 25

General functional significance of the cerebral cortex

Answer 25

Perception of special sensations (somatic, visual, auditory, olfaction)
Planning and execution of voluntary movements
Emotions and behavior
Mental functioning
Memory

Question 26

Dysfunctions of cerebral cortex

Answer 26

Usually caused by vascular hemorrhage, thrombosis or tumor

Symptoms related to specific regions of cortex affected