Voluntary Motion

Question 1

Describe the dorsal pathway leaving occipital cortex. Ventral pathway?

Answer 1

Dorsal: Goes to parietal/frontal cortex for enabling complete motor acts based on visual inputs
Allows one to play catch

Ventral: relays info to inferior temporal cortex to process visual image so that one can copy it if needed and name/recognize it

Question 2

What does the ventral intraparietal (VIP) area do?

Answer 2

From the visual cortex, information is relayed to parietal cortex V6A, PEc, medial intraparietal area, and VIP
VIP creates a rough map of the space around you

Question 3

What does the F4 in premotor cortex do?

Answer 3

From VIP, information is sent to F4
F4 creates a detailed map of space around you
Neurons here are particularly excited by proximity

Question 4

Visual information about your arm is sent to superior parietal cortex and sends input to F2. What does F2 do?

Answer 4

F2 constructs a related map of where your arm is in relationship to your body and things around you

Question 5

Anterior intrapariteal area and PFG (parts of inferior parietal cortex) contain neurons that respond to what?

Answer 5

Seeing an object to grasp (visually dominant)
Grasping an object (motor dominant)
Either condition (visuomotor neurons)

They relay their info to F5

Question 6

What does F5 do?

Answer 6

Fire with the goal, not the motor act

Question 7

Compare and contrast neural components for reaching for an object vs grasping that object

Answer 7

To reach:
Need visual map of object in relation to you
Primary visual cortex via dorsal pathway
Ventral intraparietal cortex (VIP) creates map
Relays it to F4, which creates detailed map
Parallel pathway using superior parietal cortex sends information to F2, leading to a map of where your arm is in relation to you

To grasp:
Areas of inferior parietal cortex relay information to F5
F5 codes goal of action

Both inputs are then sent on to be turned into motion

Question 8

Describe the premotor cortex

Answer 8

Receives sensory information required to move (particularly F4 and F5 - the ventral parts)
Dorsal applies the rules that determine whether it is appropriate to move
Identifies the intent of motion and decides what motion to produce

Question 9

Describe the supplementary motor cortex

Answer 9

Supplementary motor area (SMA): postural control
Pre-supplementary area (pre-SMA): plans motor program required to make action occur
Organize motor sequences
Acquire motor skills
Executive control (particularly the decision to switch actions/strategies)

Question 10

Describe the primary motor cortex

Answer 10

Precentral gyrus
Controls specific movements
Regions of body that do fine motions have proportionally high representation
Arranged in columns
Stimulation of any given column produces a specific movement

Question 11

What do layers 4 and 5 do?

Answer 11

Layer 4 receives sensory input (muscle and joint proprioceptors)
Layer 5 becomes output for corticospinal (pyramdal) pathway

Question 12

What are the two sets of neurons in each column? What are teh two kinds of columns?

Answer 12

One to start motion, one to maintain it as long as necessary

On/off for agonist muscle, off/on for antagonist muscle

Question 13

Describe how primary, premotor, and supplementary motor cortices participate in control of voluntary motion

Answer 13

Premotor: determines whether it is okay to move and identifies goal and motion required to meet that goal

Supplementary motor: postural controls, identifies specific motor sequence required, changes tactics if necessary

Primary motor: codes individual motions required to reach goal

Question 14

What is the role of the cerebellum?

Answer 14

Sequence complex actions
Correct force/direction
Balance and eye movements
Learning of complex actions

Question 15

Describe spinocerebellum

Answer 15

Two regions:
Central (light) - postural control
Either side of vermis: force and direction

Question 16

Describe cerebrocerebellum

Answer 16

Lateral regions
Plan complex motions
Sequence

Question 17

Describe vestibulocerebellum

Answer 17

Balance/eye movements

Future - not current

Question 18

Describe inputs and outputs for spinocerebellum for postural control

Answer 18

Inputs: vestibular, visual and auditory, efferent copy (what brain sends to muscle

Outputs: interpositus nucleus, fastigial nucleus, to rubrospinal tract

Question 19

Describe inputs and outputs for spinocerebellum for force and direction

Answer 19

Inputs: muscle afferent, efferent copy

Outputs: interpositis nucleus, to rubrospinal tract

Question 20

Describe inputs and outputs for cerebrocerebellum for complex motions

Answer 20

Inputs: cerebral cortex (all)

Outputs: dentate, back to cortex

Question 21

Describe inputs and outputs for vestibulocerebellum for planning balance

Answer 21

Input: vestibular apparatus

Output: fastigial nucleus to vestibular nuclei; ascend or descend

Question 22

Compare and contrast functional division of cerebellum and their role in motor control (inputs and outputs)

Answer 22

Spinocerebellum (vermis): postural controls using efferent copy, vestibular, hearing, and auditory input
Spinocerebellum (lateral): feedback control of motion using efferent copy and muscle afferent information
Cerebrocerebellum: planning complex motions, learning
Vestibulocerebellum: future balance/vestibular

Question 23

What areas of the brain are associated with producing voluntary motion?

Answer 23

Primary motor cortex
Supplementary motor cortex
Premotor cortex
Prefrontal cortex
Parietal cortex