Motor Circuit

Question 1

What does the basal nuclei motor circuit manage?

Answer 1

• Movement selection and control

- Regulates muscle contraction, muscle force, and sequencing of movements.

Question 2

Motor circuit regulates which UMNs are to be excited and which need to be inhibited to carry out the?

Answer 2

Desired movement and prevent unwanted movement

Question 3

Motor circuit major outputs to the VA and VL nuclei of the?

Answer 3

Thalamus and rostral brainstem.

• Regulation of muscle tone
• No direct LMN connections

Question 4

Motor circuit lesions cause an imbalance of facilitation and inhibition of?

Answer 4

Too much movement or too little movement not paraylsis.

Question 5

Motor Circuit - Direct pathway overall -

Answer 5

Excitatory to movement = move more

Question 6

Motor Circuit - Indirect pathway overall -

Answer 6

Inhibitory to movement = move less

Question 7

Motor Circuit - Hyperdirect pathway overall -

Answer 7

Strong inhibition of movement

Question 8

The hyperdirect pathway?

Answer 8

Stops movement in progress when a new movement is desired

Question 9

The direct pathway?

Answer 9

facilitates specific desired movements

Question 10

The indirect pathway?

Answer 10

prevents unwanted movements

Question 11

Output nuclei are the nuclei that provide most of the output from the basal nuclei to other regions of the brain and brainstem. Output nuclei are the?

Answer 11

Globus pallidus internus

Substantia nigra pars reticularis

Question 12

Output nuclei - T/F - The more active the output nuclei are the less overall movement there will be?

Answer 12

T

Question 13

What three ways the output nuclei decrease overall movement. First way?

Answer 13

Inhibits the motor thalamus (VA and VL nuclei)
-Inhibiting the thalamus, the ability of the thalamus to activate the motor cortices is reduced, thus less excitation of UMNs in the descending motor pathways

Question 14

What three ways the output nuclei decrease overall movement. Second way?

Answer 14

Inhibit the rostral brainstem
-Inhibiting the rostral brainstem, inhibition of the reticulospinal tracts to the trunk and girdle muscles is reduced and axial tone increases

Question 15

What three ways the output nuclei decrease overall movement. Third way?

Answer 15

Inhibit the rostral brainstem

-Inhibiting the rostral brainstem, excitation of stepping pattern generators is reduced, decreasing initiation of gait

Question 16

Motor circuit - balance between excitatory and inhibitory influences on the output nuclei determines the amount of?

Answer 16

movement

Question 17

What are the two types of synapses?

Answer 17

Excitatory (generates EPSP)

Inhibitory (generates IPSP)

Question 18

If one nucleus is prevented from inhibiting a second nucleus, the second nucleus is now said to be?

Answer 18

Disinhibited

-The type of synapse between these nuclei is still inhibitory.

Question 19

A direct (GO) pathway starts at the ____ and ends at the ____?

Answer 19

putamen

output nuclei

Question 20

Direct (GO) pathway overall ____ movement?

Answer 20

increases

Question 21

Direct (GO) pathway - putamen wants to ____ the output nuclei?

Answer 21

inhibit

Question 22

Direct (GO) pathway - (Putamen to Output nuclei) decreased activity of output nuclei leads to:

______ activity in corticospinal and corticobrainstem tracts increasing limb and face movements.

______ activity in reticulospinal tracts reducing trunk and girdle muscle tone.

Answer 22

increased

decreased

Question 23

Direct (GO) pathway - (Putamen to Output nuclei) -
____ activity of output nuclei leads to:

• ______ activation of stepping pattern generator
• Together these changes leads to an overall ____ in movement.

Answer 23

Decreased

Increased

Increase

Question 24

Indirect (no GO) pathway - starts in _____ and ends at the ____ passing through the ____ and the sutbthalamus nucleus along the way.

Answer 24

putamen

output nuclei

globus pallidus externus

Question 25

Indirect (no GO) pathway - overall ____ movement?

Answer 25

decreases

Question 26

Indirect (no GO) pathway - putamen wants to inhibit the GPe. GPe wants to inhibit the STN. STN wants to ____ the output nuclei.

Answer 26

excite

Question 27

Indirect (no GO) pathway - (putamen to GPe to STN to Output) -
_____ activity of output nuclei leads to:

• _____ activity in corticospinal and corticobrainstem tracts, decreasing limb and face movements.
• ____ activity in reticulospinal tracks increasing trunk and girdle muscle tone.

Answer 27

Increased

Decreased

Increased

Question 28

Indirect (no GO) pathway - (Putamen to GPe to STN to Output Nuclei) -
-____ activity in output nuclei leads to:

• ____ activation of stepping pattern generators for gail.
• Together these changes lead to an overall ___ in movement.

Answer 28

Increased

Decreased

Decrease

Question 29

The more active the output nuclei are, the ___ we move.

Direct (GO) pathway ____ movement by ______ the output nuclei

The indirect (No Go) pathway _____ movement by _____ the output nuclei

Answer 29

Less

Increases, inhibiting

Decreases, exciting

Question 30

Hyperdirect Pathway

Very strong _____ of the STN directly by the ____

Answer 30

excitation

cortex