Cerebellum

Question 1

3 layers of gray matter in cerebellum (superficial to deep)

Answer 1

1. Molecular layer: few neurons, but has basket and stellate cells.
2. Purkinje fibers: purkinje cell bodies.
3. Granular layer: contains granule cells and golgi cells.

Question 2

Purkinje cells

Answer 2

Major efferents in cerebellum.
Inhibitory (GABA).
Many dendrites.

Question 3

Granule cells

Answer 3

Only excitatory neurons (glutamate).

Small.

Question 4

Stellate cells

Answer 4

Synapse w/ purkinje cells and inhibit them.

Question 5

Golgi cells

Answer 5

Inhibitory (GABA)

Question 6

Basket cells

Answer 6

Synapse w/ purkinje cells and inhibit them (GABA).

Question 7

2 afferent fibers

Answer 7

Climbing fibers: from inferior olive. Synapse w/ purkinje cells.
Mossy fibers: from all else. Synapse w/ granular cells.

Question 8

Vestibulocerebellum

Answer 8

Functional name for flocculonodular lobe.
Gets info from vestibular receptors and sends output to vestibular nuclei.
Influences eye movements and postural muscles of head and body.

Question 9

Spinocerebellum

Answer 9

Functional name for vermis and paravermal region.
Gets somatosensory info and helps in internal feedback from spinal interneurons and sensorimotor cortex.
Functions to control ongoing movement.

Question 10

Cerebrocerebullum

Answer 10

Input from cerebral cortex via pontine nuclei.

Functions in coordination of voluntary movements, planning of movements, timing.

Question 11

Posterior spinocerebellar tract

Answer 11

Unconscious proprioception from lower limb.
1st order neurons enter via DRG and ascend in GF.
These neurons synapse in nucleus dorsalis of Clarke.
2nd order neurons ascend in posterior spinocerebellar tract) and enter the cerebellum by the inferior cerebellar peduncle.

Question 12

Vermis vs. paravermal region

Answer 12

Vermis is for medial UMNs and paravermal region is for lateral UMNs.

Question 13

Cuneocerebellar tract

Answer 13

Unconscious proprioception from upper limb.
1st order neuron enters via DRG and ascends in CF.
1st order neurons synapse in cuneate nucleus.
2nd order neurons from accessory cuneate nucleus to cerebellum via inferior cerebellar nucleus.

Question 14

Superior cerebellar peduncle

Answer 14

Major efferent route from globose, emboliform and dentate nucleus. Afferents from anterior spinocerebellar tract.

Question 15

Middle cerebellar peduncle

Answer 15

Afferent fibers from pontine nuclei relayed to cortex.

Question 16

Inferior cerebellar peduncle

Answer 16

Mostly afferent pathways from spinal cord.

Question 17

Deep nuclei (4)

Answer 17

Fastigial
Globose
Emboliform
Dentate

Question 18

What is important to know about the anterior spinocerebellar tract?

Answer 18

That it decussates twice

Question 19

Cerebellar lesions affect:

Why?

Answer 19

IL side, because the tracts cross twice.

Question 20

Ataxia

Answer 20

Common to all cerebellar lesions.

Voluntary, normal strength, jerky and inaccurate movements, but NO hyperstiffness.

Question 21

Lesions of vestibulocerebellum will have what symptoms? (4)

Answer 21

Nystagmus
Truncal ataxia
Truncal instability (titubation)
Can’t tandem walk

Question 22

Lesions of spinocerebellum will have? (2)

Answer 22

Gait and truncal ataxia.

Question 23

Midline ataxia and sx

Answer 23

Ataxic syndromes caused by vestibulocerebellar and spinocerebellar disease.

• truncal instability
• gait ataxia

Question 24

Dysdiadochokinesia

Answer 24

Can’t do rapidly alternating movements

Question 25

Dysmetria

Answer 25

Can’t move accurately an intended distance

Question 26

Appendicular ataxia

Answer 26

Caused by dysfunction of cerebellar hemispheres