Cerebellum

Question 1

General functions of cerebellum?

Answer 1

• Coordinating movements
• Maintaining posture
• Nondiscriminatory sensory info
• Motor learning
• Procedural tasks

Question 2

What characterizes lesions of the cerebellum?

Answer 2

Motor deficits (no paralysis though)

Question 3

What are the deep cerebellar nuclei?

Answer 3

• Dentate nucleus
• Emboliform nucleus
• Globose nucleus
• Fastigial nucleus

Question 4

Order of grey matter layers?

Answer 4

Pia - Molecular layer - Purkinje layer - Granular layer - White matter

Question 5

Purkinje cells function and NT?

Answer 5

• Provide output from cerebellar cortex
• Inhibit cerebellar and vestibular nuclei
• GABA

Question 6

Granule cell function and NT?

Answer 6

• Only excitatory neurons

- Glutamate

Question 7

Stellate cells function?

Answer 7

Synapse with Purkinje cells and INHIBIT them

Question 8

Golgi cell function and NT?

Answer 8

• Inhibitory neurons

- GABA

Question 9

Basket cells function and NT?

Answer 9

• Synapse with Purkinje cells and INHIBIT them

- GABA

Question 10

Which fibers are afferent fibers?

Answer 10

Mossy fibers and climbing fibers

Question 11

Where do climbing fibers originate from?

Answer 11

Inferior olive (medulla)

Question 12

Where do mossy fibers originate from?

Answer 12

Spinal cord, reticular formation, vestibular system and pontine nuclei

Question 13

Purpose of climbing fibers?

Answer 13

• Excitatory influence on Purkinje cells

- Convey info regarding movement errors to cerebellum

Question 14

Purpose of mossy fibers?

Answer 14

• Convey somatosensory, arousal, equilibrium and cerebral cortex motor info to cerebellum
• Synapse with granulocytes

Question 15

Where do mossy and climbing fibers sent axons to?

Answer 15

Deep cerebellar nuclei

Question 16

Functions of vestibulocerebellum

Answer 16

• AKA flocculonodular lobe
• Receives info from CN III and vestibular receptors
• Sends output to vestibular nuclei
• Influences eye movements and postural muscles of head and body

Question 17

Functions of spinocerebellum

Answer 17

• AKA vermis/paravermal region
• Somatosensory info, internal feedback from spinal interneurons and sensorimotor cortex
• Controls ongoing movement via brainstem descending tracts

Question 18

Where are medial upper motor neurons housed?

Answer 18

Vermis

Question 19

Where are lateral upper motor neurons housed?

Answer 19

Paravermal region

Question 20

Where is the cerebrocerebellum located?

Answer 20

Lateral hemispheres of cerebellum

Question 21

Functions of cerebrocerebellum

Answer 21

• AKA pontocerebellum
• Receives input from cerebral cortex via pontine nuclei
• Coordination of voluntary movements, planning/timing of movements

Question 22

Afferents entering cerebellum from vestibular system?

Answer 22

• Enter vestibulocerebellum
• Vestibular nuclei
• CN VIII

Question 23

Afferents entering cerebellum from SC?

Answer 23

• Enter spinocerebellum
• Anterior spinocerebellar tract
• Posterior spinocerebellar tract
• Cuneocerebellar tract

Question 24

Afferents entering cerebellum from cerebral cortex?

Answer 24

• Enter cerebrocerebellum
• Cortico-pontocerebellar
• Cortico-olivocerebellar
• Cortico-reticulocerebellar

Question 25

Which tract is the only one to have climbing fibers?

Answer 25

Cortico-olivocerebellar

Question 26

Purpose and tract of posterior spinocerebellar tract?

Answer 26

- Axons carry unconscious proprioception from LE - 1st order neurons enter via DRG and ascend in FG - Synapse @ nucleus dorsalis of Clark - 2nd order neurons ascend in dorsolateral funiculus - Enter cerebellum via inferior cerebellar peduncle

Question 27

What spinal levels is dorsal nucleus of Clark @?

Answer 27

C8-L2

Question 28

Purpose and tract of cuneocerebellar tract?

Answer 28

- Axons carry unconscious proprioception from UE - 1st order neurons enter via DRG and ascend in FC - Synapse @ accessory cuneate nucleus (lower medulla) - 2nd order neurons ascend to cerebellum - Enter cerebellum via inferior cerebellar peduncle

Question 29

Posterior spinocerebellar tract... IL or CL?

Answer 29

IL

Question 30

Cuneocerebellar tract... IL or CL?

Answer 30

IL

Question 31

Anterior spinocerebellar tract... IL or CL?

Answer 31

Crosses 2x, but still IL

Question 32

Tract for info from frontal/parietal cortex?

Answer 32

To red nucleus - inferior olive (crosses midline) - inf. cerebellar peduncle - cerebellar cortex (deep nuclei) OR to pontine nuclei (crosses midline) - middle cerebellar peduncle - cerebellar cortex (deep nuclei)

Question 33

Tract for info from SC?

Answer 33

SC - inf. cerebellar peduncle - deep nuclei

Question 34

Tract for info from vestibular nuclei?

Answer 34

SC - inf. cerebellar peduncle - deep nuclei

Question 35

Fibers @ sup. cerebellar peduncle?

Answer 35

Efferents from globose, emboliform and dentate nuclei | Afferents from Ant. Spinocerebellar tract

Question 36

Fibers @ mid. cerebellar peduncle?

Answer 36

Afferents from pontine nuclei - cortex

Question 37

Fibers @ inf. cerebellar peduncle?

Answer 37

Afferents from SC

Question 38

Function of vestibulocerebellum?

Answer 38

Eye movements and neck/trunk movements

Question 39

Function of spinocerebellum?

Answer 39

Axial/LE movements and gait/station

Question 40

Function of cerebrocerebellum?

Answer 40

Precise, coordinated movements of extremities | mainly UE

Question 41

Where does cerebrocerebellum send efferents through?

Answer 41

Dentate nucleus - Premotor cortex

Question 42

Where does spinocerebellum send efferents through?

Answer 42

Interposed/fastigial nucleus - motor cortex and brainstem

Question 43

Where does vestibulocerebellum send efferents through?

Answer 43

Vestibular nuclei - LMN in SC and brainstem

Question 44

How do cerebellar lesions affect body?

Answer 44

- Unilateral lesions affect IL side | - Ataxia

Question 45

Describe ataxia

Answer 45

Voluntary, normal muscle strength, jerky/inaccurate movements not associated with hyper stiffness - Wide gait - Fall toward lesion

Question 46

Lesions of vestibulocerebellum?

Answer 46

- Nystagmus - Truncal ataxia (difficulty maintaining sitting/standing balance) - Truncal instability (titubation... can't tandem walk)

Question 47

Lesions of spinocerebellum?

Answer 47

- Gait and truncal ataxia (wide/staggering base)

Question 48

Midline ataxia

Answer 48

- D/t vestibulocerebellar and spinocerebellar disease - Truncal instability (titubation/gait ataxia) - Equilibratory ataxiasq

Question 49

Lesions of cerebrocerebellum?

Answer 49

- Dysarthria - Ataxic gait - Decomposition of movements

Question 50

Describe limb ataxia manifestations

Answer 50

- Dysdiadochokinesia (inability to rapidly alternate mvmts) - Dysmetria (inability to accurately move intended distance - Action (intention) tremor during voluntary mvmt

Question 51

Appendicular ataxia

Answer 51

- D/t dysfunction of cerebellar hemispheres - Ataxia of extremities - Ataxia of speech (scanning dysarthria) - Hypotonia - Dysmetria - Dysdiadochokinesia

Question 52

Cerebellar Ataxia

Answer 52

- Romberg + - Cannot stand w/ feet together (w/ or w/o open eyes) - Normal vibratory/proprioceptive sense/ankle reflex

Question 53

Sensory Ataxia

Answer 53

- Can stand with feet together (w/ open eyes) - Romberg + when eyes closed - Abnormal vibratory/proprioception and ankle reflexes