3.13.14 28 Clinical Cerebral Cortex

Question 1

What areas are associated with the primary somatosensory cortex? What manifests with lesions of these areas?

Answer 1

3, 1, 2

Contralateral hypesthesia and astereognosis

Question 2

What area is associated with the association cortex? The secondary somatosensory cortex? What results from lesions?

Answer 2

5, 7

• Contralateral astereognosis
• Inability to recognize forms and body position (primarily a right hemispheric lesion)

Question 3

What area is associated with the supramarginal gyrus? Why is this area important? What results from lesions?

Answer 3

40

• Somatosensory, auditory, and visual input
• Apraxia, aphasia, neglect (primarily a right hemispheric lesion)

Question 4

What areas are associated with the superior parietal lobe?

Answer 4

5, 7

Question 5

What area is associated with simultanagnosia, optic ataxia, and hemispatial neglect?

Answer 5

Posterior parietal cortex

Question 6

What is simultanagnosia?

Answer 6

Inability to see more than one object at a time

Question 7

What is optic ataxia?

Answer 7

Deficit in directing reach under visual guidance;

Cannot be explained by motor, somatosensory, or field deficits

Question 8

What is hemispatial neglect?

Answer 8

Decreased awareness for the side of the body contralateral to the lesion; typically a right parietal lobe lesion, affecting the left body

Question 9

What is associated with posterior parietal cortex lesions?

Answer 9

Simultanagnosia
Optic ataxia
Hemispatial neglect (typically in right hemisphere)

Question 10

What type of lesion typifies Balint’s Syndrome?

Answer 10

Bilateral lesions in parieto-occipital cortex

Question 11

What symptoms are characteristic of Balint’s Syndrome?

Answer 11

Psychic paralysis of gaze (difficulty directing gaze; pt will often move head to view objects)
Optic ataxia (difficulty reaching)
Simultanagnosia (difficulty seeing more than one object)

Question 12

What areas are associated with the inferior parietal lobe?

Answer 12

40 (supramarginal area) and 39 (angular area)

Question 13

What abilities/behaviors is the inferior area of the left parietal lobe associated with?

Answer 13

Language
Skilled movement
Simple math

Question 14

What abilities/behaviors is the inferior area of the right parietal lobe associated with?

Answer 14

Spatial and non-spatial cognition
Attention/arousal
Memory

Question 15

What abilities/behaviors are the superior areas of the left AND right parietal lobes associated with?

Answer 15

Reaching, grasping, tactile exploration
Oculomotor function
Visually-guided action
Intention to perform movements

Question 16

What is the primary visual area (#)? What geniculate nucleus/body is it associated with?

Answer 16

Area 17

Lateral geniculate body

Question 17

What is the secondary visual (visual association) area? What results from lesions to this area?

Answer 17

Areas 18 and 19
Visual hallucinations (uninhibited imagination)
Agnosia (can’t associate objects)
Alexia (can’t read)

Question 18

What is Anton’s Syndrome? What is the cause?

Answer 18

aka Anton-Babinski Syndrome
Cortical blindness with denial of visual impairment (uninhibited imagination)
Bilateral damage to occipital lobes (from primary visual cortex to association cortex)

Question 19

What is the area for the angular gyrus (#)? What is its importance? What is associated with damage to the angular gyrus and sub-angular optic radiations of the left hemisphere? Right hemisphere?

Answer 19

39
Receives heteromodal (multiple modes) input
Blends visual, tactile, spatial, and auditory input
Left: Gerstmann’s syndrome
Right: Hemi-neglect
Either: contralateral hemianopia

Question 20

What is Gerstmann’s syndrome? What lesion causes it?

Answer 20

Agnosia (can't ID by sight)
Left-Right confusion
Agraphia (can't write)
Acalculia (can't solve math problems)
Caused by left hemisphere damage to angular gyrus (area 39)

Question 21

What is apperceptive visual agnosia?
What is Associative visual agnosia?
Which is more common?

Answer 21

Apperceptive: rare; impairment of shape perception and ability to copy, recognize, or discriminate shapes
Associative: more common; inability to associate visual object with its meaning (can copy images, but cannot tell what they are)

Question 22

What causes associative visual agnosia?

Answer 22

Localized damage to inferior temporal lobes and adjacent occipital cortex (inferior longitudinal fasciculus, or the ventral/”what” visual pathway)

Question 23

What are the two visual pathways?

Answer 23

Dorsal = posterior parietal = fronto-occipital fasciculus = “where” pathway

Ventral = Inferior temporal = Inferior longitudinal fasciculus = “what” pathway

Question 24

What are the two main cell types of the lateral geniculate nucleus/body?

Answer 24

Magno cells = large cell bodies with quick operation, but low detail

Parvo cells = small cell bodies with slow operation, but more detailed information

Question 25

What are the primary auditory areas? Another name?

Receive information from which geniculate nucleus/body?

Answer 25

41 and 42
Located in Heschl’s gyrus
Medial geniculate nucleus

Question 26

What is the auditory association cortex area? What is the result of left hemisphere lesion? Right?

Answer 26

22; superior temporal gyrus
Left: Wernicke’s aphasia
Right: sensory dysprosodia (inability to perceive of speech intonations, emotion)

Question 27

What is the primary motor area? What is the premotor area?

Answer 27

4, 6

Question 28

What is the supplementary motor cortex area? What is its purpose?

Answer 28

6

Programs complex motor sequences and bilateral movements

Question 29

What is the frontal eye field area? What is its purpose?

Answer 29

8

Control gaze in contralateral direction

Question 30

What is the are for the prefrontal cortex? What results from lesions (famous patient)?

Answer 30

9-12, important for working memory
Impaired social behavior
Decreased initiation
Suck and grasp responses
Incontinence
Abulia (lack of will or motivation)
Mutism