The Cerebellum

Question 1

What are the main functions of the cerebellum? (3)

Answer 1

-Coordinated movements
-Synergy
-Involved in balance / posture
(-linguistic / cognitive functions)

Question 2

What is synergy?

Answer 2

Coordination of time / force / duration of muscle action.

Question 3

Describe the general structure of the cerebellum.

Answer 3

• 2 cerebellar hemispheres
• Dorsal - vermis in midline
• Ventral – tonsils either side of midline
• Flocculus – under mid cerebellar peduncle

Question 4

What are the 3 functional subdivisions of the cerebellum?

Answer 4

• Vestibulocerebellum
• Spinocerebellum
• Cerebrocerebellum

Question 5

What is another name for the vestibulocerebellum?

Answer 5

Archicerebellum.

Question 6

What is another name for the spinocerebellum?

Answer 6

Paleocerebellum.

Question 7

What is another name for the cerebrocerebellum?

Answer 7

Neocerebellum.

Question 8

What is the vestibulocerebellum composed of?

Answer 8

• Flocculonodular lobe

- Part of vermis

Question 9

What is the spinocerebellum composed of?

Answer 9

• Most of vermis

- Adjacent regions of hemispheres

Question 10

What is the cerebrocerebellum composed of?

Answer 10

Lateral parts of hemispheres.

Question 11

What is the function of the vestibulocerebellum?

Answer 11

Coordinates muscles involved in balance and constancy of visual fields.
-e.g. keeping gaze still while moving head

Question 12

Where does the vestobulocerebellum receive input from?

Answer 12

Vestibular part of inner ear.

-vestibular nerve&raquo_space; vestibular nucleus&raquo_space; inf cerebellar peduncle&raquo_space; flocculonodular lobe and vermis

Question 13

Where is the vestibular nucleus located?

Answer 13

In the pons and rostral medulla.

Question 14

Where does the vestobulocerebellum send information to?

Answer 14

• CN III, IV and VI via medial longitudinal fasciculus

- LMNs via vestibulospinal tract

Question 15

What muscles contract when you move your head to the right in order to keep your gaze constant?

Answer 15

• Medial rectus of right eye

- Lateral rectus of left eye

Question 16

What is the spinocerebellum composed of?

Answer 16

• Most of vermis

- Adjacent regions of hemispheres

Question 17

What is the function of the spinocerebellum?

Answer 17

Coordinates muscles involved in posture and locomotion.

-ipsilateral

Question 18

What information does the spinocerebellum receive and from where?

Answer 18

Proprioception and other sensory info from spinal cord
» inf cerebellar peduncle
» vermis and adjacent hemispheres

Question 19

What does the spinocerebellum receive information about proprioception from?

Answer 19

• Muscle spindles

- Golgi tendons

Question 20

What are the 3 places that gather proprioception information?

Answer 20

• Eyes
• Semi-circular canal (ear)
• Muscle spindle/golgi tendon

Question 21

What is the cerebrocerebellum composed of?

Answer 21

Lateral parts of hemispheres.

Question 22

What is the function of the cerebrocerebellum?

Answer 22

Coordinates movements of distal limbs.
-especially fine movement of hands
Also thought to have role in motor learning.

Question 23

Where does the cerebrocerebellum receive input from? (2)

Answer 23

MOTOR CORTEX – via pontine nucleus
» mid cerebellar peduncle

INFERIOR OLIVARY NUCLEI&raquo_space; inf cerebellar peduncle

Question 24

What is one difference between the spinocerebellum and the cerebrocerebellum?

Answer 24

SPINOCEREBELLUM – knows what muscles are doing

CEREBROCEREBELLUM – knows about intended movements

Question 25

Give an example of motor learning (cerebrocerebellum).

Answer 25

Blink response. - puff >> blink - sound + puff >> blink - sounds alone >> blink

Question 26

Damage to what structure stops the blink response?

Answer 26

Inferior olivary nucleus.

Question 27

How does the cerebellar homunculus match the function of the specific subdivisions?

Answer 27

``` Vestibulocerebellum = most central (>> CNS). Spinocerebellum = more lateral (>> vertebral column muscles). Cerebrocerebellum = most lateral (>> distal limb muscles). ```

Question 28

Does the cerebellum work ipsilaterally or contralaterally?

Answer 28

Ipsilaterally. | -coordinates actions of muscles on the same side

Question 29

Does the cerebellum receive all of its information from the same side?

Answer 29

No, may receive information from the same side, but crosses midline at pyramids. >> overall IPSILATERAL response

Question 30

What direction would you fall off a chair if you damaged the right side of the cerebellum?

Answer 30

Fall of to the right.

Question 31

What are the effects of cerebellar damage?

Answer 31

Incoordination / ataxia. | -still able to move, but disordered

Question 32

What is truncal ataxia?

Answer 32

Inability to stand / sit without falling.

Question 33

What lesion causes truncal ataxia?

Answer 33

Midline lesion affecting vestibulocerebellum. | -commonly due to medulloblastoma

Question 34

What is gait ataxia?

Answer 34

Lower limb most affect >> staggering, wide-based gait.

Question 35

What lesion causes gait ataxia?

Answer 35

Lesion of spinocerebellum.

Question 36

Why is gait ataxia common in chronic alcholics?

Answer 36

Due to degeneration of cerebellar neurons in paravermal areas.

Question 37

What does a cerebellar hemisphere lesion lead to?

Answer 37

Incoordination of voluntary movement. | -particularly in upper limb

Question 38

What are the possible causes of cerebellar hemisphere lesions?

Answer 38

Vascular Degenerative Trauma

Question 39

What are the main symptoms of cerebellar hemisphere lesions? (5)

Answer 39

- Tremor of intent - Past pointing (dysmetria) - Adiadochokinesia - Dysarthria - Nystagmus