Posterior parietal cortex (PPC)

Question 1

where is the PPC

Answer 1

parietal lobe - caudal to S1

Question 2

what are the two areas of the PPC

Answer 2

superior parietal lobule (SPL)
inferior parietal lobule (IPL)

Question 3

what is in the SPL

Answer 3

2 functionally distinct areas
- involved in the processing of sensory feedback
areas 5 and 7

Question 4

what is in the IPL

Answer 4

2 anatomically distinct areas
- involved in perception of space and tool use
supramarginal gyrus and angular gyrus

Question 5

where is the SPL located

Answer 5

PPC - caudal to S1
- superior / dorsal to intraparietal sulcus

Question 6

what does area 5 in the SPL do

Answer 6

integrates tactile and propiroceptive info
- provide info about the orientation of hte body and interactions with the environment
(integration of all areas before it)

Question 7

what does area 7 in the SPL do

Answer 7

integrates visual, auditory, and somatosensory info
- processed in the PPC

Question 8

what are the inputs into the SPL

Answer 8

PMd - inputs related to selection, planning, and control of reaching mvmts
PMv - inputs for selection, planning, and control of hand and arm mvmts
S1 - somatosensory feedback for the planning, initiation, and control of ongoing motor actions
visual cortex - visual input about objects in the environment

Question 9

what is the somatotopic organisation of the PPC (both SPL and IPL)

Answer 9

show more overlap in the representation of hte body than observed in S1 and M1
- don’t have the same homunculus division

Question 10

what are the 3 outputs from the SPL

Answer 10

PMd
- multimodal sensory info for upper limb mvmts
PMv
- multimodal sensory info for grasping (more visual info involved in voluntary grasping mvmts)
PFC (prefrontal cortex)
- selecting and planning voluntary motor actions

Question 11

where is the IPL located

Answer 11

PPC - caudal to S1
- inferior / ventral to intraparietal sulcus

Question 12

what is the function of the supramarginal gyrus in the IPL

Answer 12

receives visual, auditory, and somatosensory feedback
- rostral portion is specialised for the use of hand held tools

Question 13

what is the function of the angular gyrus in the IPL

Answer 13

receives auditory and visual feedback
- involved in attention, complex language functions such as reading, writing, and math (spatial manipulations)

Question 14

what are the inputs into the IPL

Answer 14

S1 - somatosensory feedback for the planning, initiation, and control of ongoing motor actions
PMv - inputs related to the selection, planning, and control of hand mvmts
— main input to SMG
visual cortex - related to the location, shape, and size of objects in the environment

Question 15

what are the 2 outputs from the IPL

Answer 15

PMv
- multimodal sensory info important for grasping
- important role in visuomotor transformations involved in grasping mvmts
PFC
- important for selecting and planning voluntary motor actions

Question 16

what is the function of mirror neurons in the IPL (SMG)

Answer 16

• important for understanding the actions of others
• important for representing the overall goal of a grasping mvmt regardless of whether we perform it or watch someone else do it

Question 17

when are the mirror neurons in SMG active during actions

Answer 17

• fires during graps and release of object
• same thing happens when the subject watches someone else do the task
• can be selective for different types of observed actions
• neurons in the same area of the brain can selectively activate for different types of observed actions