Motor disorders

Question 1

In the SNc, D1 neurones do what?

Answer 1

Activate the direct pathway

Question 2

In the SNc, D2 neurones do what?

Answer 2

Inhibit the indirect pathway

Question 3

What are the symptoms of Parkinson’s disease?

Answer 3

Akinesia (reduction/absence of movement)
Bradykinesia (Slowness)
Rigidity
Tremor (Pill rolling)
Poor balance
Speech problems
Can progressively cause depression, anxiety, cognitive dysfunction and sleep disturbances

Question 4

How does Parkinson’s disease develop?

Answer 4

Loss of DA cells from the SNc (Primary)
Degeneration of the Nigro-striatal pathway
Genetic mutations

Question 5

Knock-on consequences of SNc degeneration

Answer 5

Increases activation of GPi via indirect
Decreases inhibition via direct
Increases inhibition of thalamus

Loss of cortico-spinal output

Question 6

How is Parkinson’s disease treated?

Answer 6

Combination therapy with L-DOPA (first line)
- combined with decarboxylase inhibitors (carbidopa, benserazide)

DA receptor agonists

Retard degradation
- MAO and COMT inhibitors

DA release

Question 7

What are the symptoms of Huntington’s disease?

Answer 7

Chorea (involuntary jerking)
Grimacing
Balance and gait problems
Cognitive decline, memory loss, depression
Swallowing and speech
10-20 years survival

Question 8

How does Huntington’s disease develop?

Answer 8

Cell death in caudate/putamen
Impaired striatal-nigral and striato-pallidal transmission
Nigro-striatal is preserved
Mutant huntingtin gene

Question 9

Knock-on consequences of striatal degeneration

Answer 9

Loss of caudate neurones
Decreased inhibition of GPe (thus increased inhibition of STN)
Decreased excitation of GPi
Decreased inhibition of thalamus

Increase in cortico-spinal output (Hyperkinesia)

Question 10

How is Huntington’s disease treated?

Answer 10

Baclofen (antispasticity)
D2 Antagonists (e.g chlorpromazine)
Treat symptoms e.g depression
Neuroprotection
Caspase inhibitors (apoptosis?)

Question 11

Cerebellar dysfunction leads to

Answer 11

Ataxia
Fine motor control, gait and co-ordination

Treat the symptoms

Question 12

Cerebellar dysfunction can be caused by

Answer 12

Genetic, trauma, stroke, alcohol, drugs

Question 13

Obsessive compulsive disorder is caused by

Answer 13

Lesions in the caudate/putamen (repetitive motor responses)

Treated with SSRIs

Question 14

Tourette’s Syndrome is caused by

Answer 14

Increased activity in nigro-striatal pathway

Treated with D2-antagonists