Motor Systems: Basal Ganglia

Question 1

Hyperkinetic dyskinesia (ballismus due to loss of excitatory drive to GPi). Where is the most likely spot of this lesion?

Answer 1

Subthalamic nucleus

Question 2

What happens during Parkinson’s disease; essentially a lesion to substantia nigra pars compacta?

Answer 2

• Bradykinesia
• Rigidity
• Rest tremor of 4-7 Hz
• Postural instability

Question 3

Where is the most likely spot of a lesion resulting in:

• flexion dystonia/flexion posturing
• Dystonia/rigidity representing an increase in motor activity

Answer 3

Globus pallidus. Loss of normal tonic inhibitory activity of GPi on VA/VL of thalamus.

Question 4

What striatal lesion results in a more complex behavior disorders such as:

• vulgarity, impulsiveness
• Increased appetite, polydipsia
• Hypersexuality

Answer 4

Caudate

Question 5

What striatal lesion is more motoric in nature, affecting stereotypic behavior?

Answer 5

Putamen

Question 6

What is the pathology and symptoms of Huntingtons disease?

Answer 6

Initially death of spiny neurons in neostriatum (particularly GABA/ENK group), resulting in chorea. All of striatum eventually dies. Develop akinesia as direct pathway is affected.