Cerebellum

1
Cerebellum

• More cells in cerebellum than rest of nervous
  system combined
• Receives sensory info from somatosensory,
  vestibular, visual and auditory areas

2
3 divisions of cerebellum

• Vestibulocerebellum
• Spinocerebellum
• Neocerebellum
• Different lesions produce different clinical
  deficits

3
Vestibulocerebellum

• Input from output to brainstem vestibular
  nuclei
• For balance
• For coordinating eye body movements
• Vestibulo-ocular reflex
• Allows eyes to remain fixed on an object despite
  head or body movements

4
Vestibulocerebellum

• Cerebellar nystagmus
• Inability to fixate on object.
• eyes drift away from it, with rapid return.

5
Vestibulocerebellum

• Damage ? decreased reflexes
• Postural instability
• Experience nausea

6
Spinocerebellum

• Ascending sensory inputs via S.C.
• Descending motor outputs
• Damage ? problems with smooth control of motor
  movements
• Problems walking
• Bowlegged stance

7
Spinocerebellum

• Damage ? rapid pointing often extends past target
• Hypermetria
• Damage ? difficulty stopping movement
• As arm approaches target, goes into oscillations

8
Neocerebellum

• Control of voluntary movements

9
Neocerebellum

• Damage leads to
• Clumsy movements
• Hypermetria
• Especially in sequences of gestures
• Movements req. coordination of many body parts
• Prolonged initiation of movements

10
Neocerebellum

• Lesions result in deficits similar to
  spinocerebellum
• Neocerebellum - planning movements
• Spinocerebellum regulating actual performance

11
Cerebellum

• Alcohol may affect cerebellum
• Sobriety tests often assess cerebellar
  functioning
• Balance
• Touching finger to nose