7. Motor Disorders

Question 1

What does the superior cerebellar peduncles attach the cerebellum to?

Answer 1

Attaches the cerebellum to the midbrain.

Question 2

What does the middle cerebellar peduncles attach the cerebellum to?

Answer 2

Attaches the cerebellum to the pons.

Question 3

What does the inferior cerebellar peduncles attach the cerebellum to?

Answer 3

Attaches the cerebellum to the medulla.

Question 4

Via what structure does the cerebellum communicate with the cortex?

Answer 4

Via the thalamus.

Question 5

What structure separates the cerebellum from the pons?

Answer 5

The fourth ventricle.

Question 6

What is the role of the vermis of the cerebellum?

Answer 6

The vermis regulates trunk musculature.

Question 7

What is the role of the lateral cerebellum hemispheres?

Answer 7

The lateral cerebellar hemispheres regulars distal structures - limbs.

Question 8

What two symptoms do lesions in the vermis of the cerebellum cause? If the lesion extends, what other symptom can it cause?

Answer 8

Vermis lesions - truncal ataxia and abnormal gait.

Extension of lesions in the vermis - compression of the fourth ventricle leading to hydrocephalus.

Question 9

What are the 6 symptoms of cerebellar hemisphere lesions?

Answer 9

Dysdiadochokinesis.
Ataxia.
Nystagmus.
Intention tremor.
Slurred speech.
Hypotonia.

Question 10

What is the role of basal ganglia?

Answer 10

Motor function - communicates with the cortex and cerebellum to aid with the initiation of movement.

Question 11

In which basal ganglia are dopaminergic neurones found?

Answer 11

In the substantia nigra pars compacta.

Question 12

What is the overall net effect of dopamine in the direct and indirect basal ganglia pathways?

Answer 12

Motor cortex stimulation via the thalamus.

Question 13

What is the pathological cause of Parkinson’s disease, and so what affect does this have on the direct and the indirect basal ganglia pathways?

Answer 13

Degeneration of the substantia nigra, causing dopamine deficiency.
Direct pathway - still stimulatory on the cortex, just less stimulation encourages.
Indirect pathway - now inhibitory on the cortex.

Question 14

What 4 general symptoms do basal ganglia disorders cause?

Answer 14

Abnormal motor control.
Altered posture.
Affected muscle tone.
Dyskinesia.

Question 15

What are the 3 cardinal symptoms of Parkinson’s disease? Name 3 other associated symptoms.

Answer 15

Cardinal - bradykinesia, resting tremor and hypotonia.

Other - hypophonia, reduced facial expression, micrographia, dementia and depression.

Question 16

What pathological changes in the brain occur in Huntington’s disease, and what affect does this have on the indirect pathway?

Answer 16

Loss of GABA neurones.
Indirect pathway switches off, stimulation of the thalamus, and so overstimulation of the cortex, hence can lead to jerking movements.

Question 17

What is the genetic inheritance of Huntington’s disease?

Answer 17

Autosomal dominant.

Question 18

Give 3 symptoms of Huntington’s disease

Answer 18

Chorea, dystonia, incoordination, cognitive decline and behavioural difficulties.

Question 19

Huntington’s disease is associated with cell loss in which basal ganglia structure?

Answer 19

Striatum - made up fo the putamen and caudate nucleus.

Question 19

What happens pathologically in the brain in hemiballismus, and so what affect does this have on the indirect basal ganglia pathway?

Answer 19

Subthalamic nuclei damaged, so reduced ability to stimulate the globus pallidus interna, and therefore the globus pallidus interna cannot inhibit the thalamus as effectively. The thalamus stimulates the cortex more, leading to inappropriate movements.

Question 20

What is the main symptom of hemiballismus?

Answer 20

Unilateral abnormal movement

Question 21

What does hemiballismus often occur secondary to?

Answer 21

Sub-cortical stroke.