Lecture 11 - Contributions of Cerebellum to Motor Functions

Question 1

What are the functions of the cerebellum and what results from its removal?

RL11 S25

Answer 1

Not essential for locomotion.

Functions:

• sequences motor activities
• compares actual movements to intended
• makes corrective adjustments

Removal results in highly abnormal movements.

Question 2

What are the zones of the cerebellum?

RL11 S26

Answer 2

Vermis (medial):
-control of axial body, neck, shoulders, and hips

Intermediate zone:
-control of extremities

Lateral zone:
-planning of sequential motor movements

Question 3

What are the intracerebellar nuclei and where do they send fibers to?

RL11 S27

Answer 3

Fastigial nucleus:

• controls trunk movement
• fibers to reticular formation and vestibular nucleus

Dentate, emboliform, and globose nuclei:

• controls extremity movement
• fibers to red nucleus

Question 4

What are the cell layers of the cerebral cortex?

RL11 S28

Answer 4

• granular
• Purkinje
• molecular

Question 5

What are the inputs of the cerebral cortex (origin and spike type), the outputs, and what cells provide lateral inhibition to output cells?

RL11 S28-30

Answer 5

Input (both synapse with Purkinje cells):

• mossy fibers from multiple centers; simple, stimulatory spikes; synapses with Purkinje cells and others
• climbing fibers from medullary olives; complex, stimulatory spikes; condition the Purkinje cells (only synapse with Purkinje cells)

Output:
-Purkinje (inhibitory)

Lateral inhibition of output:

• basket cells
• stellate cells

Question 6

What is the vestibulocerebellum?

RL11 S31

Answer 6

Consists of flocculonodular lobes and vermis.

Fibers from vestibular system and oculomotor system.

Controls pendular movements

Question 7

What is the spinocerebellum?

RL11 S33

Answer 7

Consists of vermis and intermediate zones.

Compares intended movements with actual movements.

Sends output to motor cortex and magnocellular zone (red nucleus).

Question 8

What is the cerebrocerebellum?

RL11 S34

Answer 8

Consists of lateral zones.

Plans in advance of actual movement and is involved in skilled movement.

Question 9

Want are the tracts that form the mossy fibers and climbing fibers?

RL11 S35-36

Answer 9

Mossy fibers:
-corticopontocerebellar
-vestibulocerebellar
-reticulocerebellar
-spinocerebellar
All terminate on granule cells cells. 

Climbing fibers:
-olivocerebellar
Terminate on Purkinje cells

Question 10

What is ataxia?

RL11 S38

Answer 10

Uncoordinated movement

Question 11

What is adiadochokinesia?

RL11 S38

Answer 11

Inability to perform rapid, alternating movements

Question 12

What is dysarthria?

RL11 S38

Answer 12

Slurred speech

Question 13

What is nystagmus?

RL11 S38

Answer 13

Abnormal, twitching movement of the eyes

Question 14

What is hypotonia?

RL11 S24

Answer 14

Muscle weakness