6.1.3 Cerebellum Disorders

Question 1

What is the anatomy of the cerebellum?

Answer 1

Midline vermis and two laterally placed hemispheres

Question 2

What does each part of the cerebellum do?

Answer 2

Vermis-deals with trunk

Hemispheres- corresponding ipsilateral side of the body

Question 3

How do the cerebellar peduncles communicate with the rest of the CNS?

Answer 3

Superior cerebellar peduncle-midbrain

Middle-pons

Inferior-medulla

Question 4

In relation to the ventricular system where does the cerebellum sit?

Answer 4

Above the fourth ventricle

Cerebellar lesions can cause hydrocephalus

Question 5

What are the functions of the cerebellum?

Answer 5

Sequencing and co-ordination of movements

Uses sensory information to decide upon most appropriate sequence of movements to perform an action

Question 6

What does the cerebellum co-ordinate with to decide appropriate movement?

Answer 6

Basal ganglia

Question 7

What type of inputs does the cerebellum have lots of?

Answer 7

Profuse sensory inputs from proprioceptive neurones and sensory cortices

Question 8

Outline the cerebellar pathway

Answer 8

Cortico-pontocerebellar pathway

Axons from primary cortex decussate at the pons

Axon then goes to the contralateral cerebellar hemisphere

Cerebello-thalamo-cortical pathway

Axon from contralateral hemisphere then decussates and synapses at the thalamus before going back to the primary motor cortex

Corticospinal pathway

Primary motor cortex axon then decussates at medullary pyramid and continues down in the corticalspinal pathway

Question 9

What would a right-sided cerebellar lesion cause?

Answer 9

Right-sided cerebellar function loss as axons decussate to left side in the cerebello-thalamo-cortical pathway to the primary motor cortex

Axons from the primary motor cortex then decussate back to right side in the corticospinal pathway

Ergo leading to ipsilateral loss

Question 10

What are the signs of cerebellar disease?

Answer 10

DANISH
Dysdiadochokinesia- difficulty with rapidly alternating movements

Ataxia- unsteady gait, result of difficulty sequencing lower limb muslce contractions as well as loss of unconscious proprioception from lower limbs

Nystagmus- flickering eye movements due to malcoordination of extraocular muscles

Intention tremor-treamor that worsens as a target is approached

Slurred speech (dysarthria)- malcoordination of laryngeal and tongue musculature

Hypotonia