PHYS: Voluntary Motion

Question 1

What areas are associated with the control of voluntary motion?

Answer 1

Question 2

The dorsal visual pathway contains axons from the occipital cortex that travel to the parietal/frontal lobe and this input allows us to:

Answer 2

Complete motor acts based on visual input

Ex. catching a ball

Question 3

What does VIP (ventral intraparietal area) do?

Answer 3

Creates a rough map of the space around you

Question 4

What does F4 do?

What are they excited by?

Answer 4

Creates a detailed map of the space around you.

Proximity (the closer the object, the more likely to fire)

Question 5

Where is F2 located? What does it do?

Answer 5

In the premotor cortex

Map of Body

It is the end result of the dorsal pathway (reaching), and constructs a related map of where your arm is in relationship to your body + the things around you

Question 6

What is the order of the dorsal (reaching) pathway?

Answer 6

1. Visual cortex
2. VIP (rough map)
3. F4 (detailed map)
4. F2 (related map pf body + space)

Question 7

The anterior intraparietal area + PFG are involved in what pathway? They respond to what neurons?

Answer 7

Grasping

Visuomotor Neurons (need to see + motor)

Question 8

What is the function of F5 neurons?

Answer 8

They fire w/ the goal of the action (no motor)

Question 9

What is the pathway for grasping an object?

Answer 9

1. PFG/AIP
2. F5
3. sends sensory info required to move to premotor cortex

Question 10

Both, grasping + reaching an object are what visual pathway?

Do these encode a motor act?

Answer 10

Dorsal visual pathway

No

This pathway applies the rules that determine whether it is appropriate to move

Question 11

What is the function of the premotor cortex?

Answer 11

It identifies the intent of motion and decides what motion to produce.

Determins whether itis okay to move

Question 12

What two divisions make up the supplementary motor cortex?

Answer 12

1. Supplementary motor area (SMA) - postural control
2. Pre-supplementary area (Pre-SMA) - plans the motor program required to make the action occur

(sequence of motion)

Question 13

Organizing motor sequences acquireing motor skills, + executive control = what area?

Answer 13

Supplementary Motor Cortex

Question 14

The primary motor cortex does what?

Answer 14

Codes the individual motions required to reach the goal.

Its arranged in 6 columns –> stimulation of any given column produces a specific mvmt (greys anatomy brain surgery)

Question 15

Which layer of the primary motor cortex recieves sensory input?

Answer 15

4

Question 16

Which layer of the primary motor cortex becomes the output for the corticospinal pathway?

Answer 16

Layer 5

Question 17

What 2 sets of neurons are found in each column?

Answer 17

One to start motion

One to maintain motion

Question 18

What do neighboring columns contain?

Answer 18

Related motions

Question 19

What are the 2 kinds og columns?

Answer 19

1. = on/off agonist muscle
2. on/off antagonist muscle

Question 20

What is the role of the cerebellum in producing voluntary motion?

Answer 20

Sequencing complex actions

Correct force/direction

Balance + eye movements

Learning of complex actions

Question 21

What is the spinocerebellum responsible for?

Answer 21

central - postural control

vermis - force + direction

ballistic motions

Question 22

What is the cerebrocerebellum responsible for?

Answer 22

Sequence (ex. steps of a surgery, muscians) + plan complex motions + learning

Question 23

Future balance + eye mvmts is taken care of by?

Answer 23

Vestibulocerebellum

Question 24

Input: Vestibular

Output: Vestibular n.

Answer 24

Vestibulocerebellum

Question 25

What are the inputs + outputs for cerebrocerebellum?

Answer 25

Input: cerebral cortex related to motion output: dentate n.

Question 26

Inputs + outputs for spinocerevellum (lateral):

Answer 26

Imput: efferent copy + muscle afferent info Output: Interpositus

Question 27

Spinocerebellum (vermis) iputs + outputs:

Answer 27

Imputs: efferent copy, vestibular, hearing + auditory input output: interpositus + fastigial n.

Question 28

How does the basal ganglia aid in voluntary motion? How?

Answer 28

They help **initiate mvmt** + plan and program it (control beginning + end) Via inhibition (GABA) + withdraw of that inhibition

Question 29

What is the nigrostriatal path in the basal ganglia?

Answer 29

It goes from SNPC (substantia niagra pars compacta) --\> Striatum Tonically active Has dopamine (indicates 2 pathways)

Question 30

Which basal ganglia pathway uses D1 vs D2?

Answer 30

D1 = Direct D2 = Indirect

Question 31

What is the direct pathway?

Answer 31

D1 receptors Excited by dopamine _Allows motion_

Question 32

What is the indirect pathway?

Answer 32

D2 I = inhibts motion **when active** Inhibited by dopamine Excited by EAA/Ach

Question 33

Describe the striational GABA-ergic pathway:

Answer 33

Direct pathway

Question 34

Describe the indirect pathway: -which step is excitatory (EAA)

Answer 34

-subthalamic nucleus --\> SNPR + GPi

Question 35

To produce motion we must: ______ the direct pathway + _______ the indirect pathway.

Answer 35

activate direct inactivate indirect

Question 36

Review:

Question 37

How do we inhibit motion?

Answer 37

By activating the indirect pathway via the intrastriatal cholinergic pathway

Question 38

Planning of complex motor actions + carrying out of "thought" processes happens where?

Answer 38

Prefrontal cortex

Question 39

In order to **plan** complex motor actions, what area gets involved?

Answer 39

Parieto-temporal-occipital association area + motor cortex (supplementary motor cortex + premotor cortex) + cerebrocerebellum

Question 40

Interactions between the frontal, premotor, SMC, and the basal ganglia determine:

Answer 40

IF the motion will occur

Question 41

Once the motion is planned + approved, columns in the primary motor cortex are activated and carry the action potentials of the pyramidal cells to the alpha-motor neurons to innervate the muscles needed to complete the motion.

Answer 41

The brain activates the alpha AND gamma motor neurons so that the muscle spindle doesn't change its firing rate. To stretch the muscle, they BOTH will be inhibited.

Question 42

Once motion has started, what is called upon to make sure the motion is correct?

Answer 42

Spinocerebellum