Exam #6: Basal Ganglia Function

Question 1

Define akinesia.

Answer 1

Lack of movement

Question 2

Define chroea.

Answer 2

Abnormal brief, random, twitch-like involuntary movement (dance-like)

Question 3

Define bradykinesia.

Answer 3

Slowness in the execution of movement

Question 4

Define atheotosis.

Answer 4

Slow, worm-like, writhing movements

Question 5

Define hemiballismus/ ballismus.

Answer 5

Involunatary, violent, flinging movements of a limb while awake
- Ballismus= bilateral

Question 6

Define dyskinesia.

Answer 6

General term for involuntary movements

Question 7

Define freezing of gait.

Answer 7

Seen in PD, patients will:

1) Suddenly be unable to start walking
2) Stop moving forward while walking

Question 8

Define festinating gait.

Answer 8

Abnormal gait seen in PD with small shuffling steps & absence of arm swing

Question 9

What are the structures that compose the basal ganglia?

Answer 9

• Caudate
• Putamen
• Globus pallidus (internal & external segments)
• Subthalamic nucleus
• Substantia nigra (pars reticulata & pars compacta)

Question 10

Outline the nigrotriatial pathway. What NT is important in this pathway?

Answer 10

SNc to Striatum

• DA
• Has both excitatory and inhibitory effects

Question 11

Outline the corticostriate pathway. What NT is important in this pathway?

Answer 11

Cortex to striaum

• Excitatory
• Release glutamate

Question 12

Outline the pathway from the GPe to GPi. What NT is important in this pathway?

Answer 12

Striatum to GPe= GABA/ enkephalin (path. in Huntington’s)

Striatum to GPi= GABA

Question 13

Is GABA excitatory or inhibitory?

Answer 13

Inhibitory

Question 14

Is Glutamate excitatory or inhibitory?

Answer 14

Excitatory

Question 15

What are the symptoms of PD?

Answer 15

• Resting tremor
• Rigidity (“cogwheel”)
• Slowness of movement
• Postural instability

Question 16

Which transmitter system is most severely damaged in Parkinson’s Disease?

Answer 16

DA

Question 17

Damage to which part of the basal ganglia causes Parkinson’s disease?

Answer 17

SNc

Question 18

What are the symptoms to Huntington’s Disease?

Answer 18

• Chorea
• Dementia
• Slow voluntary movements

Question 19

What is the location of the lesion that causes hemiballismus?

Answer 19

Lesion to the contralateral subthalamic nucleus

Question 20

What are the two functional loops of the basal ganglia?

Answer 20

Direct & indirect pathways

Question 21

What is the general function of the direct pathway?

Answer 21

Excitation

Question 22

What is the general function of the indirect pathway?

Answer 22

Inhibition

Question 23

Draw the direct pathway.

Answer 23

p. 105

Question 24

Draw the indirect pathway.

Answer 24

p. 105

Question 25

What is the corpus striatum?

Answer 25

Neostriatum + paleostriatum = putamen + caudate nucleus + globus pallidus

Question 26

What is the neostriatum?

Answer 26

Striatum i.e. putamen + caudate nucleus

Question 27

What is the paleostriatum?

Answer 27

Pallidum i.e. globus pallidus

Question 28

Where do the main afferents to the basal ganglia synpase?

Answer 28

Striatum i.e. putamen + caudate nucleus

Question 29

Where do the main efferent from the basal ganglia emerge?

Answer 29

Globus pallidus

Question 30

What is the general circuit of the basal ganglia?

Answer 30

1) Cortex 2) Stratium 3) Pallidum 4) Thalamus

Question 31

What are the four functional loops of the basal ganglia?

Answer 31

1) Body movement loop - Motor cortex - Internally generated movements 2) Oculomotor loop - Frontal eye fields - Saccadic eye movements 3) Prefrontal loop - Dorsal PFc - Initiation & termination of cognitive processes 4) Limbic loop - Addiction to drugs of abuse - Behavior & motivation