Basal Ganglia

Question 1

What is the overall function of the basal ganglia?

Answer 1

Modulate the activity of the motor cortex and descending pathways

Question 2

The basal ganglia get massive ______ inputs from the _______

Answer 2

excitatory (glutamate); cerebral cortex

Question 3

What is another word for the ventral striatum?

Answer 3

Nucleus accumbens

Question 4

What makes up the corpus striatum?

Answer 4

The nucleus accumbens, Caudate, Putamen, and globus pallidus

Question 5

What makes up the stiatum or the neostriatum

Answer 5

The Caudate and Putamen

Question 6

What makes up the input end of the basal ganglia?

Answer 6

The nucleus accumbens, caudate, and putamen

Question 7

What makes up the output of the basal ganglia?

Answer 7

The internal globus pallidus and the substantia nigra: Pars Recticulate (GABAergic inhibitory)

Question 8

What separate the caudate nucleus from the putamen??

Answer 8

The internal capsule

Question 9

What makes up the lenticular nucleus?

Answer 9

The Putamen and Globus pallidus (GPe and GPi)

Question 10

What are the major recipients of the excitatory afferents to the basal ganglia?

Answer 10

The GABAnergic cells in the striatum and the ventral striatum

Question 11

Where do frontal lobe afferents project?

Answer 11

The caudate head and putamen

Question 12

Where do the parietal and occipital afferents project?

Answer 12

The caudate body

Question 13

Where do the temporal lobe afferents project?

Answer 13

caudate tail

Question 14

Where does the primary motor and sensory cortex afferents project?

Answer 14

Putamen

Question 15

Where do the premotor and supplementary motor area afferents project?

Answer 15

Caudate head

Question 16

Where does the limbic cortex project?

Answer 16

Nucleus accumbens

Question 17

The GPi projects to the ________ via 2 fiber tracts: __________ and ___________

Answer 17

thalamus: ansa lenticularis and the lenticular fasciculus

Question 18

The SNr cells bypass the ______ entirely and project directly to the _______ superior colliculus.

Answer 18

thalamus; superior colliculus

Question 19

What does the direct pathway do?

Answer 19

excites thalamic neurons

Question 20

Describe the direct pathway

Answer 20

1) cerebral cortex sends excitatory input to the striatum and ventral striatum
2) they then send inhibitory input to the SNr and GPi which are turned off (they are also inhibitory to the thalamus)
3) The thalamus then can send excitatory info to the cortex

Question 21

What does the indirect pathway do?

Answer 21

Inhibits thalamic neurons

Question 22

Which nuclei has excitatory inputs?

Answer 22

Subthalamic nuclei

Question 23

Describe the indirect pathway

Answer 23

1) excitatory input from the cerebral cortex goes to the striatum and ventral striatum
2) these then inhibit the GPe
3) inhibition to the subthalamic nucleus is turned off
4) This then ACTIVATES the The GPi and SNr
5) these inhibit thalamic activity

Question 24

What is extrapyramidal syndrome?

Answer 24

An upset in the balance of these two pathways

Question 25

What 4 factors must you consider when categorizing tremors?

Answer 25

1) rhythmicity (regular or irregular) 2) Amplitude (small or large) 3) Frequency (slow or fast) 4) which body parts are affected?

Question 26

What is chorea?

Answer 26

involuntary, fast, irregular, mostly distal limb movements that resemble dancing

Question 27

What is athetosis?

Answer 27

involuntary, slower, writhing, mostly distal limb movements that resemble the movements of a snake

Question 28

What is myoclonus?

Answer 28

involuntary movements that are small and rapid (a jerk), usually of bilateral proximal limbs and trunk

Question 29

What causes Huntington's?

Answer 29

selective, genetically initiated loss of striatal neurons in the indirect pathway

Question 30

What causes Hemiballism

Answer 30

damage of the subthalamic nucleus which results in a decrease in function of the indirect pathway

Question 31

What does acetylcholine do in the basal ganglia?

Answer 31

It synapses on the striatal neurons that project to GPi and GPe which inhibits the direct pathway and excites the indirect pathway

Question 32

What are the other functions of the basal ganglia?

Answer 32

Rewards and cognitive function

Question 33

What does the nigrostriatial pathway do?

Answer 33

dual effect of exciting the direct pathway while simultaneously inhibiting the indirect pathway (through D1 and D2 receptors)

Question 34

What causes Parkinson's disease?

Answer 34

loss of the dopaminergic neurons in the sustantia nigra pars compacta

Question 35

The basal ganglia receives a very important dopaminergic input from ______ (to caudate and putamen) and the ________(to N. accumbens) that are both in the ________

Answer 35

the substantia nigra: pars compacta; ventral tegmental area; midbrain