Basal Ganglia

Question 1

LO 39 Basal ganglia: list the components of basal ganglia

Answer 1

• caudate nucleus
• lanetiform nucleus (putamen and external globus pallidus)
• subthalamic nucleus
• substantia nigra
• ventral pallidum, claustrum, nucleus accumbens, nucleus basalis of Meynert

Question 2

Give the functions of basal ganglia

Answer 2

• elaborating associated movements (eg swinging arms while walking)
• moderating and coordinating movement (suppressing unwanted movements)
• performing movements in order

Question 3

LO 39 Label the diagram of basal ganglia

Question 4

Describe the pathology and signs of Parkinson’s disease.

Answer 4

Neurodegeneration of the dopaminergic neurons that originate in the substantia nigra and project to the striatum

Signs:

• bradykinesia
• hypomimic face
• akinesia
• rigidity
• tremor at rest

NIGRO-STRIATAL PATHWAY

Question 5

LO41 Describe the pathology and signs of Huntingtons’ disease.

Answer 5

Pathology:

• Genetic neurodegenerative disorder
• Chromosome 4, autosomal dominant
• CAG repeat
• Degeneration of GABAergic neurons in the striatum, caudate and then putamen

Signs:

• Choreic movements (Chorea) : rapid jerky involuntary movements of the body; hands and face affected first; then legs and rest of body
• Speech impairment
• Difficulty swallowing
• Unsteady gait
• Later stages, cognitive decline and dementia

Question 6

Name the 3 divisions of the cerebellum. Give the function of each.

Answer 6

1. Vestibulocerebellum:
   
   • Regulation of gait, posture and equilibrium
   • Coordination of head movements with eye movements
2. Spinocerebellum:
   
   • Coordination of speech
   • Adjustment of muscle tone Coordination of limb movements
3. Cerebrocerebellum:
   
   • Coordination of skilled movements
   • Cognitive function, attention, processing of languageEmotional control

Question 7

LO41 Explain the relevance of pathways into and out cerebellum

Answer 7

• 2 input pathways, 1 output pathway
• Made up of 3 layers:
  
  • Molecular layer (outermost)
  • Piriform layer: Purkinje cells
  • Granular layer
• Inferior olive projects to purkinje cells vua climbing fibres
• all other input to granule cells via mossy fibres and then onwards via parallel fibers
• all output from Purkinje cells via deep nuclei

Question 8

Name and describe the 3 syndromes caused by cerebral dysfunction.

Answer 8

1. Vestibulocerebellar Syndrome: Damage (tumour) causes syndrome similar to vestibular disease leading to gait ataxia and tendency to fall (even when patient sitting and eyes open)
2. Spinocerebellar syndrome: Damage (degeneration and atrophy associated with chronic alcoholism) affects mainly legs, causes abnormal gait and stance (wide-based)
3. Cerebrocerebellar or Lateral Cerebellar Syndrome: Damage affects mainly arms/skilled coordinated movements (tremor) and speech