S2W9 - Sensorimotor

Question 1

Which system is afferent, and what does this mean?

Answer 1

sensory, meaning it detects (senses) stimuli

Question 2

Which system is efferent, and what does this mean?

Answer 2

motor, meaning it sends signals responding to the stimuli

Question 3

Ballistic mvmts

Answer 3

mvmts that do. not require feedback, e.g. swatting a fly

Question 4

Posterior Parietal Cortex damage symptoms

Answer 4

neglect (right) - a deficit in deployment of attention
apraxia (left) - disorder of voluntary mvmt in out-of context situations

Question 5

Posterior Parietal Cortex input and output

Answer 5

Input - integrates sensory info
Output - frontal, dorsolateral prefrontal, secondary motor, frontal eye field

Question 6

Dorsolateral Prefrontal Cortex purpose

Answer 6

respond to object characteristics and locations
respond to task execution from beginning to completion

Question 7

Dorsolateral Prefrontal Cortex output

Answer 7

Output - secondary motor, primary motor, frontal eye field

Question 8

Secondary Motor Cortex purpose

Answer 8

elicits complex mvmt bilaterally

Question 9

Secondary Motor Cortex parts

Answer 9

supplementary motor area, premotor cortex, cingulate motor areas

Question 10

Secondary Motor Cortex output

Answer 10

Output - (mainly) primary motor cortex

Question 11

Mirror Neurons location and purpose

Answer 11

location - ventral premotor area
purpose - encode for specific goal objects (disregarding if a stranger of themselves are interacting with it)

Question 12

Primary Motor Cortex purpose

Answer 12

elicits motor response towards a goal (rather than individual mvmt)
identify objects by touch
moves small body parts independently (e.g. a finger)
damage rarely debilitating - not sole region of mvmt

Question 13

Primary Motor Cortex input and output

Answer 13

generic - major point of convergence for all sensorimotor signals, and departure to the rest of the body

Question 14

Cerebellum purpose

Answer 14

responsible for coordinates and modulation of actions
responsible for accuracy and control of direction, force, velocity and amplitude of mvmt
responsible for adaptation of mvmt in changing conditions
i.e. where the action is, what the action is, and if it changes. damage severely debilitating

Question 15

Cerebellum input

Answer 15

Input - primary motor, secondary motor, brainstem motor nuclei, somatosensory system, vestibular system, cerebellum

Question 16

Basal Ganglia purpose

Answer 16

responsible for motivation in mvmt, like mvmt vigor (e.g. colour change on piano), and supressing motor activity (e.g. yawn in a lec)

Question 17

Basal Ganglia input and output

Answer 17

General - reciprocal connections w/ cortex and cerebellum

Question 18

Descending Motor Pathways structure

Answer 18

move from primary motor cortex
(to various structures)
descending ipsilatterally or dessucating
(to various outputs)

Question 19

Dorsolateral - direct

Answer 19

1) move from primary motor cortex
2) to Medullary pyramid
3) dessucating
4) to the spine and distal limbs (wrists, hands, digits, toes)

Question 20

Dorsolateral - indirect

Answer 20

1) move from primary motor cortex
2) to the red-nucleus (midbrain)
3) dessucating
4) to the cranial nerves and face muscles, then further down spinal cord to the distal muscles (legs, arms)

Question 21

Ventromedial - direct

Answer 21

1) move from primary motor cortex
2) descending ipsilaterally
3) to the spine,
4) then innervate neurons circuits bilaterally

Question 22

Ventromedial - indirect

Answer 22

1) move from primary motor cortex
2) descend ipsilaterally
3) axons descend bilaterally

Question 23

Descending Motor Pathways differences

Answer 23

VM tracts more diffuse (become bilateral)
DL tracts terminate on contralateral half
VM neurons project to proximinal muscles - trunk and limbs
DL neurons project to distal muscles - fingers and toes

Question 24

Motor Units

Answer 24

• the smallest unit of motor activity
• a single motor neuron and all skeletal muscles it attaches to (which all fire with the single motor neuron)
• more neurons / less fibers for areas like the fingers, and vice versa for other areas like legs