Motor System + Basal Ganglia

Question 1

what are the two locations for lower motor neurons?

Answer 1

ventral horn of SC and cranial nerve motor nuclei of brainstem

Question 2

what part of brain houses nuclei of lower motor neurons for the cranial nerves?

Answer 2

brainstem

Question 3

are lower motor neurons the final common pathway for voluntary, involuntary or both?

Answer 3

Both movements

Question 4

what is the corticobulbar tract?

Answer 4

runs from cortex and synapses in brainstem to lead to innervation of cranial nerves

Question 5

early upper motor neuron injury leads to what?

Answer 5

paralysis/weakness

Question 6

late upper motor neuron syndrome leads to what?

Answer 6

babinski sign
muscle spasticity
hyperactive reflexes
no muscle atrophy

Question 7

lower motor neuron syndrome leads to what clinically?

Answer 7

hyporeflexive
flaccid paralysis
atrophy
fibrillations/fasciculation

Question 8

what are fibrillations/fasciculations?

Answer 8

spontaneous muscle twitches

Question 9

what region of the brain is important for movement inhibition and coordinates with the motor tracts?

Answer 9

basal ganglia

Question 10

what region of the brain is important for balance and coordination and coordinates with the motor tracts?

Answer 10

cerebellum

Question 11

name the five parts of the basal ganglia

Answer 11

caudate nucleus
putamen
globus pallidus 
substantis nigra
subthalamic nucleus

Question 12

where does the basal ganglia receive input?

Answer 12

cortex

Question 13

where does the basal ganglia output go?

Answer 13

thalamus

Question 14

what makes up the striatum in the basal ganglia?

Answer 14

caudate and putamen

Question 15

where is the caudate located in coronal cross section of brain?

Answer 15

just lateral to the lateral ventricles

Question 16

the caudate and putamen make up what in the basal ganglia?

Answer 16

striatum

Question 17

the cortex stimulates what in the basal ganglia to initiate response?

Answer 17

striatum

Question 18

what Nt does the cortex use to stimulate the striatum in the basal ganglia?

Answer 18

glutamate

Question 19

what are the two pathways in the basal ganglia?

Answer 19

indirect and direct

Question 20

the goal of the direct pathway of the basal ganglia is what?

Answer 20

to allow movement

Question 21

the goal of the indirect pathway of the basal ganglia is what?

Answer 21

to inhibit movement

Question 22

what is the baseline action of the thalamus?

Answer 22

to inhibit the motor function at rest

Question 23

what is the baseline action of the globus pallidus internus and pars reticulatum on the thalamus?

Answer 23

to increase thalamic inhibition of the cortex

Question 24

what are the two parts of the globus pallidus?

Answer 24

globus pallidus internus

globus pallidus externus

Question 25

what are the two parts of the substantia nigra in the basal ganglis?

Answer 25

pars reticulata | pars compacta

Question 26

what does the striatum do in the direct basal ganglia pathway when it is activated?

Answer 26

inactivates the globus pallidus internus and pars reticulata

Question 27

what Nt does the striatum use in the direct pathway to inhibit the pars reticulata and the globus pallidus internus?

Answer 27

GABA

Question 28

in the direct pathway, with the inhibition of the globus pallidus internus and the pars reticulata, what does this allow for from the thalamus?

Answer 28

thalamus is no longer inhibited by these and can increase motor movement in the cortex

Question 29

what is the modifier of the indirect and direct pathway of the basal ganglia?

Answer 29

cortex stimulates the pars compacta to dump dopamine on the striatum of the basal ganglia

Question 30

what is the dopamine receptor used by the direct pathway in the basal ganglia on the striatum?

Answer 30

D1

Question 31

what is the dopamine receptor used by the indirect pathway in the basal ganglia on the striatum?

Answer 31

D2

Question 32

once the striatum is activated by glutamate in the indirect pathway of the basal ganglia, what occurs?

Answer 32

inhibition of the globus pallidus externus using GABA

Question 33

what Nt does the indirect pathway use to inhibit globus pallidus externus?

Answer 33

GABA

Question 34

what is the normal function of the globus pallidus externus?

Answer 34

to inhibit the subthalamic nucleus

Question 35

what is the normal role of the subthalamic nucleus?

Answer 35

to stimulate the globus pallidus internus

Question 36

when the indirect pathway of the basal ganglia inhibits the globus pallidus externus what happens to the subthalamic nucleus?

Answer 36

it is no longer inhibited and can lead to more stimulation of the globus pallidus internus

Question 37

more activation of the globus pallidus internus by the decreased inhibition of the subthalamic nuclei in the indirect pathway of the basal ganglia leads to what in the thalamus?

Answer 37

more inhibition of the thalamus

Question 38

does the D2 receptor in the striatum that receives input from the pars compacta lead to stimulation or inhibition of the indirect pathway?

Answer 38

inhibition of the indirect pathway