Ch. 7.3. Movement disorders

Question 1

How does MPTP exposure influence the likelihood of Parkin-
son’s disease? What are the effects of cigarette smoking?

Answer 1

Exposure to MPTP can induce symptoms of Parkin- son’s disease. Cigarette smoking is correlated
with decreased risk of the disease.

Question 2

How does L-dopa relieve the symptoms of Parkinson’s disease?

And In what ways is L-dopa treatment disappointing?

Answer 2

L-dopa enters the brain, where neurons convert it
to dopamine, thus increasing the supply of a depleted neurotransmitter

L-dopa increases dopamine activity in spurts and in all neurons, not steadily and not just in those that need help. It does not stop the loss of neurons. It has unpleasant side effects.

Question 3

What procedure has improved the effectiveness of brain
grafts for treatment of Parkinson’s disease?

Answer 3

Results improved somewhat after physicians began giving drugs to suppress the immune response

Question 4

Why does damage to the basal ganglia lead to involuntary
movements?

Answer 4

Output from the basal ganglia to the thalamus is inhibitory. After damage to the basal ganglia, the thalamus, and therefore the cortex, receive less inhibition. Thus, they produce unwanted actions.

Question 5

What procedure enables physicians to predict who will or will not get Huntington’s disease and to estimate the age of onset?

Answer 5

Physicians can count the number of consecutive repeats of the combination C-A-G on one gene on chro- mosome 4. If the number is fewer than 36, the person will not develop Huntington’s disease. For repeats of 36 or more, the larger the number, the more certain the person is to develop the disease and the earlier the
probable age of onset.

Question 6

Deterioration of which axons leads to Parkinson’s disease?

Answer 6

Dopamin releasing Axons from the substantia nigra to the striatum

Question 7

People with Parkinson’s disease show the greatest impairment with which type of movement?

Answer 7

Spontaneous voluntary movements