Cerebellum

Question 1

What does the basal ganglia do?

Answer 1

Turns certain muscles on and off.

Question 2

What does the cerebellum do?

Answer 2

Ensures that the intended motor function is actually carried out (coordination and balance).

Question 3

Describe major organizational divisions of cerebellum.

Answer 3

Vermis, cerebellar hemispheres, and floccular nodular lobe (located by projecting lateral sulcus). Cerebellum is roof of fourth ventricle, held up by cerebellar peduncles. Most neurons in brain is NOT in cortex, it is in cerebellum!

Question 4

Identify the cerebellar peduncles and deep cerebellar nuclei

Answer 4

Inferior, middle, and superior cerebellar peduncles. Festigial nucleus (vermis), interposed nucleus, and dentate nucleus (cerebellar hemispheres).

Question 5

List afferent and efferent contributions of inferior cerebellar peduncles.

Answer 5

ICP: afferent fibers from spinal cord (mossy fibers), inferior olive (climbing fibers), and vestibular and cochlear nuclei (mossy fibers). Efferent fibers to vestibular nuclei.

Question 6

List afferent and efferent contributions of middle cerebellar peduncles.

Answer 6

MCP: afferent fibers from cerebral cortex by way of pontine nuclei. Left cortex->right cerebellum. Right cerebellum=right side of body.

Question 7

List afferent and efferent contributions of superior cerebellar peduncles.

Answer 7

SCP: efferent fibers from cerebral cortex to cerebellum via deep cerebellar nuclei. Afferent fibers from spinocerebellar tract.

Question 8

Define origins of mossy and climbing fibers.

Answer 8

Climbing fibers = sensory fibers from inferior olive to ICP. Mossy fibers are all other sensory fibers reaching ICP and MCP.

Question 9

Describe function of different parts of cerebellum.

Answer 9

Vermis=truncal movements, gait/balance
Cerebellar hemispheres=peripheral limb motor activities
Floccular nodular lobe=vestibular function, eye movments

Question 10

On what side of the body would a cerebellar defect appear? e.g. damage to right cerebellum = ?

Answer 10

Ipsilateral side. Damage to right cerebellum -> abnormality on right side of body.

Question 11

Describe wiring diagram of floccular nodular lobe.

Answer 11

Primary vestibular afferents, flocculonodular lobe, and festigial nuclei.

Question 12

Describe wiring diagram of vermis.

Answer 12

Vermis, interposed nuclei, red nucleus

Question 13

Describe wiring diagram of cerebellar hemispheres.

Answer 13

Dentate nucleus

Question 14

Describe the three microscopic layers of the cerebellum

Answer 14

1. Molecular layer: mainly axons and dendrites
2. Purkinje cell layer: only axons leaving cerebellar cortex. Purkinje are inhibitory to deep cerebellar nuclei.
3. Granular layer

Question 15

Describe path of mossy fibers

Answer 15

Synapse in granular layers (on granular cells), form parallel fibers, which project to purkinje cells in purkinje cell layer. Activates purkinje inhibition of deep cerebellar nuclei.

Question 16

Describe path of climbing fibers

Answer 16

Climbing fibers from contralateral inferior olive wrap around purkinje cells and activates purkinje inhibition of cerebellar deep nuclei. 1 climbing fiber per purkinje cell.

Question 17

Describe function of satellite and basket cells.

Answer 17

Inhibit purkinje inhibition of deep cerebellar nuclei.