Lecture 5: Cerebellum, CST and Motor Systems

Question 1

What is the role of cerebellum in motor control?

Answer 1

• Receives and modulates information relating to balance.
• Receives and modulates information relating to the reticular formation (controls neuron excitability, in relation to neurons that control muscles opposing gravity)
• Engages motor planning and monitoring to ensure the motor movement goes to plan.
• Highly repetitive and very swift movements are controlled by the cerebellum.

Question 2

What are the three cerebellar cortical structures?

Answer 2

1. Archicerebellum (Flocculonodular lobe and vermis)
2. Palaeocerebellum
3. Neocerebellum

Question 3

What are the deep cerebellar nuclei (output structures)

Answer 3

• Fastigial nucleus
• Interpositus nucleus
• Dentate nucleus

Question 4

What are the cerebellar systems?

Answer 4

1. Vestibulocerebellum - Balance and eye movements
2. Spinocerebellum - Balance and Posture
3. Cerebrocerebellum - Coordination of movement

Question 5

How do the cerebellar systems and cortical structures align?

Answer 5

Align:

1. Archicerebellum -> Vestivulocerebellum
2. Palaeocerebellum -> Spinocerebellum
3. Neocerebellum -> Cerebrocerebellum

Question 6

What is the clinical importance of the cerebellum?

Answer 6

• Drunken sailor gait / stance
• Dandy-walker syndrome
• Arnold-chiari malformation (CB slips down through foramen magnum)

Question 7

What is the cerebellum philosophy?

Answer 7

• Wants to answer; Where am I? (Done by knowing the tension of all muscles),
• Planning movements
• Execution of movements
  (Stop movements, plan again, modifying)

Question 8

Answer 8

Question 9

Answer 9

Question 10

Answer 10

Question 11

Answer 11

Question 12

In the brainstem where does the Vestibular nucleus project to in the cerebellum?

Answer 12

It projects to the vermis

Question 13

Where does the DCST project to in the cerebellum?

Answer 13

Projects to the paleocerebllum

Question 14

Where do the planning motor fibres project to in the cerebellum?

Answer 14

Neocerebellum

Question 15

Describe the projections of the inf. olivary nucleus to the cerebellum:

Answer 15

Very distinct climbing fibres that ascend through the inferior peduncle into cerebellum

Question 16

How does the DSCT work?

Answer 16

Monitors limb position based on golgi tendon organs and muscle spindle fibres.

(They input into laminar 7 of the spinal cord forming the beginning of the DSCT)

Question 17

Describe the structure of the cerebellar cortex

Answer 17

Question 18

Describe how the cerebellar cortex work?

Answer 18

Cerebellar inputs i.e Spinal, Cortical and etc synapse onto granule cells that extend from the granular layer to the molecular layer bifurcating and forming parrallel fibre layers. Hundreds of these synapase on a perkinje cell. These fire in a simple standard pattern. If the information received is incorrect then it can be modulated by cells that project through the inferior olivary complex to see if the plan is going correctly, that wrap around the perkinje cells. If incorrect then the ION will inhibit the cells “complex firing”.

Question 19

Where do the perkinje cells project to?

Answer 19

The deep cerebellar nuclei.

Question 20

What is the nature of the major inputs to the cerebellum?

Answer 20

Spinal

Vestibular

Motor Planning