Voluntary Motion

Question 1

Which cortical areas are associated with production of voluntary motion?

Answer 1

Primary motor cortex, supplementary motor cortex and pre-motor cortex

Question 2

What is the location and function of the primary motor cortex?

Answer 2

Located on the precentral gyrus
Controls specific movements especially those related to moving the arms/hands to the face or body
Arranged in columns

Question 3

Describe the organization of columns in the primary motor cortex

Answer 3

Layer 4 receives sensory input (muscle and joint proprioceptors, among others)
Layer 5 becomes the output for the CST pathway
Each column has two sets of neurons (one to start motion and one set to maintain it as long as necessary)
Stimulation of any given column produces a specific movement
Two types: on/off for agonist muscle and off/on for antagonist muscle

Question 4

Neighboring columns of the primary motor cortex control what?

Answer 4

Related motions, not neighboring muscles

Question 5

What are the two divisions of the supplementary motor cortex?

Answer 5

Supplementary motor area (SMA) and pre-supplementary motor area (pre-SMA)

Question 6

What is the function of the supplementary motor area (SMA)?

Answer 6

Postural control

Question 7

What is the function of the pre-supplement area (pre-SMA)?

Answer 7

Plans the motor program required to make the action occur

Question 8

What are the functions of the supplementary motor cortex?

Answer 8

Organize motor sequences
Acquire motor skills
Executive control (particularly the decision to switch actions/strategies)

Question 9

What are the functions of the pre-motor cortex?

Answer 9

Receives sensory info required to move
Identifies the intent of the motion and decides what motion to produce
Dorsal region: applies the rules that determine whether it is appropriate to move

Question 10

What are the roles of the cerebellum?

Answer 10

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

Question 11

What are the two regions of the spinocerebellum?

Answer 11

Central (vermis)

Lateral to the vermis

Question 12

What is the function of the central portion (vermis) of the spinocerebellum?

Answer 12

Postural control/adjustments to ongoing motions

Question 13

What are the inputs to the central portion of the spinocerebellum?

Answer 13

Vestibular, visual and auditory, efferent copy

Question 14

What are the outputs of the central portion of the spinocerebellum?

Answer 14

Interpositus nucleus, fastigial nucleus

To rubrospinal tract

Question 15

What is the function of the portions lateral to the vermis?

Answer 15

Force and direction of ongoing motion

Correct ongoing motions and control ballistic motions (motions so fast there isnt time to correct it)

Question 16

What are the inputs and outputs to the lateral sides of the vermis?

Answer 16

Inputs: muscle afferent and efferent copy
Outputs: interpositus nucleus to rubrospinal tract -> to SC

Question 17

What are the functions of the cerebrocerebellum?

Answer 17

Plan complex motions
Sequencing of rapid movements
Work with cortex

Question 18

What are the inputs and outputs of the cerebrocerebellum?

Answer 18

Inputs: all regions of cerebral cortex
Outputs: dentate nucleus and back to cortex

Question 19

What is the function of the vesitbulocerebellum?

Answer 19

Balance/eye movements

Question 20

What are the inputs and outputs of the vestibulocerebellum?

Answer 20

Input: vestibular apparatus (direct or indirect)
Output: fastigial nucleus to vestibular N then ascend or descend

Question 21

In general the outputs from the cerebellum are via what?

Answer 21

The deep cerebellar nuclei including dentate, fastigial and interpositus (globose and emboliform) nuclei