6.2 Basal Ganglia

Question 1

basal ganglia is normally _______, and disinhibition allows for voluntary movement

Answer 1

inhibitory

Question 2

site of excitatory input from cortex (corticostriate projections), made up of caudate nuclei and putamen, send inhibitory projections to globus pallidus

Answer 2

striatum

Question 3

inhibited by the striatum, internal output (GPi) and external (GPe), GPi inhibits thalamus, major outflow nucleus

Answer 3

globus pallidus

Question 4

inhibited by globus pallidus and cortex, projections back to globus pallidus

Answer 4

subthalamic nuclei

Question 5

inhibit striatum via dopamine

Answer 5

substantia nigra

Question 6

direct excitation path uses _____

Answer 6

D1

Question 7

indirect excitation path uses ____

Answer 7

D2

Question 8

direct path: cortex excites striatum –> striatum inhibits ____ and ___ –> thalamus is disinhibited from GPi/SNr –> excitation of motor cortex

Answer 8

globus pallidus internal and SNr

Question 9

indirect path: cortex excites striatum –> striatum inhibits ______ –> subthalamic nuclei are disinhibited –> GPi/SNr are excited –> inhibits thalamus –> inhibits motor cortex

Answer 9

globus pallidus external

Question 10

indirect path: cortex excites striatum –> striatum inhibits ______ –> subthalamic nuclei are disinhibited –> GPi/SNr are excited –> inhibits thalamus –> inhibits motor cortex

Answer 10

globus pallidus external

Question 11

dopamine: via nigrostriatal projections –> excites ____ and inhibits _____ –> excite motor cortex

Answer 11

D1, D2

Question 12

mediates D1 and D2 to give opposite effects, any inhibitory action by this neurotransmitter

Answer 12

GABA

Question 13

any excitatory action, except dopamine in nigrostriatal pathway

Answer 13

glutamate

Question 14

any excitatory action, except dopamine in nigrostriatal pathway

Answer 14

glutamate

Question 15

degeneratin of nigrostriatal projections, decreased dopamine in striatum, high inhibition of thalamus, unable to initiate movement

Answer 15

Parkinson’s disease

Question 16

treatment for parkinsons?

Answer 16

L-DOPA

Question 17

precursor of dopamine able to cross BBB, side effects are dyskinesia and wearing off

Answer 17

L-dopa

Question 18

loss of GABA neurons from striatum to GPe, leads to less inhibition of thalamus, slower/lower amplitude than ballismus

Answer 18

huntington’s chorea

Question 19

high velocity/amplitude flinging of arm, subthalamic nucleus lesion

Answer 19

hemiballismus

Question 20

involuntary writhing

Answer 20

athetosis

Question 21

present with contralateral symptoms, BG synapse to ipsilateral motor cortex

Answer 21

unilateral lesion