Basal Ganglia

Question 1

What does the basal ganglia consist of ?
(also called the extrapyramidal system
0

Answer 1

striatum (caudate and putamen), globus pallidus, substantia nigra, and the subthalamic nucleus

Question 2

Hypokinesia

Answer 2

Parkinsons

motor activity is reduced or slowed, except for resting tremor

Question 3

Hyperkinesia

Answer 3

choreoathetosis or hemiballismus

-excessive, involuntary movements

Question 4

Parkinson’s disease

Answer 4

loss of dopaminergic neurons in the substantia nigra

-net increased inhibitory output of the GPm to the ventrolateral thalamic motor nuclei–reduction in stimulation of the motor cortex

Question 5

Hemiballismus

Answer 5

destruction of the subthalamic nucleus

-net decreased inhibitory output of the GPm

Question 6

Huntington’s disease

Answer 6

loss of indirect pathway putaminal neurons to the lateral globus pallidus

• net decrease inhibitory output of GPm
• -choreoathetosis

Question 7

What are the clinical signs of Parkinson’s disease?

Answer 7

*1. resting tumor
-pill-rolling
*2. rigidity
cogwheeling
*3. bradykinesia
*4. impaired postural reflexes
-balance instability (light pushing)
5. masked facies
6. hypophonic speech-hoarse, soft and difficult to understand
7. micrographia
8. constipation, bladder dysfunction, or orthostatic hypertension
9. REM behavior sleep disorer

Question 8

How is parkinson’s diagnosed?

Answer 8

clinically

• at least 2 of the 4 primary clinical signs should be present and atypical features should be absent
• improvement with first dopaminergic medication

Question 9

What do you see in the neurons of parkinson’s?

Answer 9

loss of pigmented dopaminergic neurons in the substantia nigra
-alpha synuclein positive-Lewy bodies

grossly substantia nigra and locus ceruleus appear pale

Question 10

Treatment of PD

Answer 10

1. Levodopa-the most effective
2. combined with carbidopa (limits catabolism of levodopa)
3. COMT inhibitor -smoothes out undesirable motor fluctuations
4. MAO type B inhibitor
   - extend effects of dopamine
5. anticholinergic-control of resting tremor
6. dopamine agonists

electrode into subthalamic nucleus to inhibiting it by means of repetitive electrical stimulation

Question 11

Huntington’s disease

Answer 11

choreoathetosis, dementia, and behavior syndromes
-multiple trinucleotide repeats in huntingtin gene on chromosome 4

• caudate atrophy and frontal horns of the lateral ventricles appear relatively enlarged
  treatment: dopamine antagonists and antidepressants and catecholamine depleter