25: Basal Ganglia

Question 1

Extrapyramidal System

Answer 1

A complex network of basal ganglia, subcortical pathway, feedback loops, and indirect descending pathways

Question 2

What is the EPS involved in?

Answer 2

Crude movements of limbs (like swinging arms while walking)

Question 3

Lesion of the red nucleus

Answer 3

Ipsilateral oculomotor palsy + contralateral motor dysfunction (tremor, ataxia)

Question 4

Striatum (AKA neostriatum)

Answer 4

Caudate + putamen + nucleus accumbens

Question 5

Corpus striatum

Answer 5

Caudate + putamen + GP

Question 6

Lenticular nucleus

Answer 6

Putamen + GP

Question 7

Dorsal striatum

Answer 7

Putamen + caudate nucleus

Question 8

Basal ganglia blood supply

Answer 8

MCA

Question 9

Function of striatal loop

Answer 9

Initiate motor movement patterns

Question 10

Function of cerebellar loop

Answer 10

Adjusting intensity of motor movement patterns

Question 11

Do GP and SN fibers terminate in the same spot in the VL and VA thalamic nuclei?

Answer 11

No, different spots

Question 12

Ansa lenticularis

Answer 12

Major efferent from the GP

Question 13

Three parts of the ansa lenticularis

Answer 13

1. Pallidothalamic fiber projections: dorsal and ventral division
2. Subthalamic fasciculus: intermediate division

Question 14

Nigra thalamic fiber projections: origin and termination

Answer 14

Origin: pars reticularis of SN

Terminate in: VA and VL thalamic nuclei

Question 15

What causes Parkinson’s disease?

Answer 15

Destruction of neurons in pars compacta of substantia nigra (can also involve GP and RF)

Question 16

S/S Parkinsons

Answer 16

Bradykinesia, tremor during rest, pill-rolling tremor, rigidity, masked face, positive glabellar reflex, postural embarrassment

Question 17

Postural embarrassment

Answer 17

Responding to a backwards threat with short, choppy steps back

Question 18

Tardive dyskinesia

Answer 18

Repetitive involuntary lip smacking due to long-term use of neuroleptic meds

Question 19

What causes Huntington’s chorea

Answer 19

Destruction of GABAergic fibers in striatonigral fibers + degeneration of corpus striatum and cerebral cortex

Question 20

S/S Huntington’s chorea

Answer 20

Dementia, chorea, behavioral disturbances

Question 21

What are choreiform movements?

Answer 21

Sudden, irregular, jerky, involuntary motions

Question 22

Athetosis

Answer 22

Slow involuntary writhing movements of fingers/hands/toes; can be present with Huntington’s chorea

Question 23

What causes hemiballism?

Answer 23

Lesion of the subthalamus -> less control to GP

Question 24

S/S hemiballism

Answer 24

Contralateral violent involuntary flinging movements of limbs, hypotonus

Question 25

Syndenham’s Chorea cause

Answer 25

Infection with strep or rheumatic fever in children less than 16 years of age