Subcortical control of movement (cerebellum)

Question 1

What are the function of the cerebellum in motor function?

Answer 1

Motor correction, - learning, balance and coordination

Question 2

What are the non-motor functions of the cerebellum?

Answer 2

Activ tactile exploration and higher brain functions

Question 3

What are some signs of cerebellar disease?

Answer 3

Hypometria and response delay, ataxia (loss of coordination), and dysdiadochokinesia (incoordination/rapid alternating movements)

Question 4

What are a mnemonic (memory techniquie) of signs of cerebellar disease?

Answer 4

DANISH:
Dysdiachokinesis
Ataxia
Nystagmus
Intention tremor
Scanning/slurred speech
Hypotonia

Question 5

Describe the functional organization of the cerebellar hemipheres.

Answer 5

Cerebrocerebellum: motor planning and coordination
Spinocerebellum: control of ongoing body and limb movements
Vestibulocerebellum: posture, balance and eye movements

Question 6

What are some components of the brainstem and diencephalon related to the cerebellum?

Answer 6

Pontine nuclei (cortical input), inferior olive (movement error/correction), and cuneate & Clarke (proprioceptive input)

Question 7

What areas of the cerebral cortex projects to the cerebellum?

Answer 7

The parietal and the rostral part of the frontal

Question 8

Describe the functional organization of the major outputs from the cerebellum to the cortical motor systems.

Answer 8

Cerebellar cortex –> deep cerebellar nuclei –> through the superior cerebellar peduncle –> direct projection to subcortical targets (superior colliculus/reticular formation/vestibula nuclei) –> through the thalamus –> motor cortex

Question 9

What are the superior colliculus associated with?

Answer 9

Eye movements

Question 10

What are the reticular formation associated with?

Answer 10

planning/correcting movement

Question 11

What are the vestibular nuclei associated with?

Answer 11

Balance

Question 12

What kinds of neurons are found in the cerebellum?

Answer 12

Inputs: climbing fibres from inferior olive, mossy fibers
Output: purkinje neurons
Interneurons: granule, stellate, basket and golgi neurons

Question 13

Describe purkinje cells.

Answer 13

• GABAergic (inhibitory)
• co-activate spine synapses
• “espalier” shape enables tight packing in coronal plane

Question 14

Describe the excitatory inputs in the cerebellum.

Answer 14

Mossy fibers –> granule cells –> parallel fibers –> spine synapses on purkinje cells

Question 15

Describe the climbing fibers.

Answer 15

• covers the whole dendritic tree of purkinje cells
• all-or-nothing activation
• co-activation of climbing fibre and parallel fibre leads to LTD of the parallel fibre synapses

Question 16

Describe the interneurons in the cerebellum.

Answer 16

Golgi cells –> granule cells
Basket + stellate cells –> purkinje cells
- inhibitory
- GABA, glycine etc

Question 17

Describe the forward internal model.

Answer 17

The cerebellum predicts the sensory consequences of the motor commands and is involved in computing sensory prediction errors by comparing the predictions to the sensory feedback