Cerebellum

Question 1

What is the role of the cerebellum?

Answer 1

To compare intended movements with those that actually occur - minimise the difference between intended and actual movements

Question 2

Where is the cerebellum located?

Answer 2

Sits caudal to the cerebral hemispheres and dorsal to the pons and medulla oblongata

Question 3

Describe the structure of the cerebellum

Answer 3

Highly folded cortex of grey matter plus deep nuclei

It has white matter forming branching tracts - arbor vitae (tree of life)

Question 4

What lies immediately ventral to the cerebellum?

Answer 4

The 4th ventricle

Question 5

What is the function of the pons?

Answer 5

Act as a bridge between the spinal cord, cerebellum and cerebrum

Question 6

What is the function of the medulla oblongata?

Answer 6

Act as the neural mass responsible for involuntary movement e.g. breathing

Question 7

Name the 3 lobes of the cerebellum

Answer 7

Anterior
Posterior
Flocculonodular

Question 8

What is the function of the central vermis of the cerebellum?

Answer 8

Receives information from the trunk and the proximal limbs

Question 9

Where does the intermediate zone receive information from?

Answer 9

The distal limbs

Question 10

What are the peduncles?

Answer 10

3 stalks of white matter which communicate the deep cerebellar nuclei with other CNS structures
They contribute to the structures forming the roof of the 4th ventricle

Question 11

The caudal cerebellar peduncles carry what type of fibres and what type of information?

Answer 11

Afferent fibres carrying sensory information from vestibular organs and proprioceptors to the cerebellum

Question 12

The middle cerebellar peduncles carry what type of fibres and what type of information?

Answer 12

Afferent fibres which bring information about intended movements - brings sensory fibres in from the spinal cord

Question 13

The rostral cerebellar peduncles carry what type of fibres and what type of information?

Answer 13

Efferent fibres which decussate and run from the cerebellum to the thalamus and midbrain

Question 14

What are the 3 layers of grey matter?

Answer 14

• Granule layer
• Purkinje layer
• Molecular layer

Question 15

Which layer of grey matter contains dendrites and axons?

Answer 15

Molecular layer

Question 16

Which layer of grey matter contains dendrites of one particular nerve fibre?

Answer 16

Granule layer

Question 17

What are the two main sets of afferent axons synapsing on the deep nuclei and cortex of the cerebellum?

Answer 17

Mossy fibres

Climbing fibres

Question 18

How do deep nuclei increase motor function?

Answer 18

They have their excitatory output to the upper motor neurone tracts

Question 19

What are upper motor neurones?

Answer 19

Tracts that go from the brainstem, down the spinal cord to synapse with LMNs to pass on information to enable limb movement

Question 20

What are the 3 nerve fibre types in the cerebellum?

Answer 20

Purkinje
Mossy
Climbing

Question 21

Cerebellar function is crucial for which aspects of movement?

Answer 21

Balance, coordination and refinement

Question 22

How does the cerebellum achieve its function?

Answer 22

Constant comparison of information from the motor planning centres with input from vestibular and proprioceptive sensory organs - what was intended vs what happened

Question 23

Where are corrective signals from the cerebellum sent to?

Answer 23

Via the thalamus to the brain stem upper motor nuclei

Question 24

What is the function of the vestibulocerebellum/flocculonodular lobe?

Answer 24

Coordinates balance and eye movements in response to input from vestibular and visual systems

Question 25

What is the function of the spinocerebellum/vermis?

Answer 25

Coordinates muscle tone and movement

Question 26

What is the function of the cerebrocerebellar/lateral cerebellar hemispheres?

Answer 26

Coordinates planning of limb movements

Question 27

How is the cerebellum different in animals with a large tail?

Answer 27

The cerebellar vermis has a well-developed lobule at the rostral end called the lingula

Question 28

How is the cerebellum different in precocial and altricial animals?

Answer 28

Precocial - near-fully developed cerebellum at birth

Altricial - cerebellar development continues for weeks after birth

Question 29

What is ataxia?

Answer 29

Inability of the vestibulo and spinocerebellum to coordinate balance and movement of the axial skeleton - uncoordinated gait and balance

Question 30

Loss of input from the cerebellar cortex leads to?

Answer 30

Reduced inhibition of UMN function causing hypermetria and increased muscle tone