Parietal lobes

Question 1

Anatomical location and regions

Answer 1

posterior of the central sulcus: postcentral gyrus, superior and inferior parietal lobule including the angular gyrus and supramarginal gyrus

Question 2

Main distinct regions

Answer 2

1) Somatosensory cortex (BA 1, 2, 3, postcentral gyrus)

2) Posterior parietal lobe (BA 5, 7)

Question 3

Function of the somatosensory cortex

Answer 3

1) sensation of body areas
- contralateral orientation
- not continuous or proportionally scaled
- continuous practice can expand a specific region (e.g. hands for professional pianists)

Question 4

Effects of damage to the somatosensory cortex (6)

Answer 4

1) inability to detect touch on the contralateral side
2) unable to distinguish between one or multiple contact points
3) astereognosis: unable to appreciate textile qualities
4) “blind touch”
5) asomatognosia: loss of knowledge of condition of one’s own body
6) autopagnosia: inability to localise or name body parts

Question 5

Effects of lesions particular to BA 5, 7 and 40

Answer 5

“blind touch”

- patient does not report feeling touch but if prompted can determine the exact location where they were touched

Question 6

Function of the posterior parietal lobe

Answer 6

bodily awareness

Question 7

Effects of damage to the posterior parietal lobe

Answer 7

1) Hemi-neglect: completely neglecting the side of the body opposite to the site of the lesion
2) unable to perform mental rotation (usually after lesions to the right side)
- > unaware of problems

3) left parietal lesions include language problems like Gerstmann syndrome
4) lesions to both lobes can cause Balints syndrome: inability to see two objects when they are presented at the same time

Question 8

Visual-spatial functions of the parietal cortex

Answer 8

primarily egocentric representation: relation of objects to the person