Lecture 17: Cerebellum Flashcards by Spandana Sama

What is the function of the cerebellum?

Coordinating movements
Maintaining posture
Motor learning

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What are the four deep cerebellar nuclei?

Dentate Nucleus
Emboliform Nucleus
Globose Nucleus
Fastigial Nucleus

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How is the grey matter in the cerebellum organized?

Molecular Layer
Purkinje Layer
Granular Layer

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What layer of grey matter contains the cell bodies of basket cells and stellate cells?

Molecular layer

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What efferent fibers are from the cerebellar cortex?

Purkinje fibers

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What is the deepest layer of grey matter?

What cells does it contain?

Granular layer

Contains granule cells and a few Golgi cells

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Most gray matter neurons tend to be ____ and use the NT ____, except for granule cells.

Inhibitory

GABA

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What nuclei are inhibited by Purkinje cells?

Cerebellar and vestibular nuclei

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Which neurons in the gray matter of the cerebellum are the smallest?

What NT does it use?

Granule cells

Glutamate: only excitatory neurons!

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What grey matter cells synapse with Purkinje cells?

What is their action?

Stellate cells and basket cells from molecular layer

Inhibits Purkinje cells

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What are the afferent fibers in the gray matter?

What is their general action?

Climbing fibers and mossy fibers

Excitatory

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Where do the gray matter afferents send collateral branches?

Deep cerebellar nuclei and own receptors

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Where do the climbing fibers arise from?

Inferior olive of the medulla

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What cells do the climbing fibers synapse with?

What information does it convey?

Excitatory influence on Purkinje cells

Conveys information about movement errors

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Where do mossy fibers come from?

Almost everywhere

Spinal Cord
Reticular Formation
Vestibular formation
Pontine nuclei

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What do mossy fibers synapse with?

Granulocytes

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What information do the mossy fibers convey to the cerebellum?

Somatosensory
Arousal
Equilibrium
Cerebral cortex motor

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What is the anatomic name of the vestibulocerebellum?

Flocculonodular lobe

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What is the function of the vestibulocerebellum?

Influence eye movement
Influence postural muscles of head and body in relation to gravity
Balance and equilibrium

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What information is transmitted to the flocculonodoluar lobe?

Where does it send information to?

Receives information from vestibular receptors and visual areas

Sends ouput to vestibular nuclei

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What is the functional name for the vermis and paravermal region of the cerebellum?

Spinocerebellum

What part of the spinocerebellum is associated with the medial upper motor neurons?

Vermis

Postural muscles of trunk

What part of the spinocerebellum is associated with the lateral upper motor neurons?

Paravermal region

Moving limbs*
Gait and station*

What is the function of the vermis and paravermal region?

Control ongoing movement via brainstem descending tracts

Monitors gait and station

What information is conveyed to the spinocerebellum?

To Vermis: Somatosensory, visual, auditory, and vestibular information To Paravermis: Somatosensory information

What is the functional name of the lateral hemispheres of the cerebellum?

Pontocerebellum/Cerebrocerebellum

What is the function of the cerebrocerebellum?

Coordination of planned, timed, voluntary movements Fine movements for fractionation

Where does the Cerebrocerebellum get its informaion from? Where does it send this information to?

Input: Cerebral cortex via pontine nuclei Output: Motor and Premotor cortex

The dorsal Nucleus of Clark is found at what spinal levels?

C8-L2

What do the restiform and juxtarestiform bodies comprise?

Inferior cerebellar peduncle ## Footnote * Restiform: posterior spinocerebellar* * Juxtarestiform: cuneocerebellar*

Which cerebellar tracts carries unconscious proprioception from the lower limb?

Anterior and posterior spinocerebellar tracts

Where does the first order neuron of the posterior spinocerebellar tract enter, ascend through, and then synapse?

DRG --\> Gracile fasciculus --\> Nucleus dorsalis of Clark (C8-L2) --\> Restiform Body --\> Cerebellum

What do the axons of the cuneocerebellar tract carry?

Unconscious proprioception from the upper limb

Where do the first order neurons of the cuneocerebellar tract enter, ascend, and then synapse?

Enter via DRG --\> Ascend in cuneate fasciculus --\> Synapse in accessory/external/lateral cuneate nucleus (lower medulla) --\> Juxtarestiform Body --\> Cerebellum

What is the path of the anterior spinocerebellar tract?

1. Lamina of dorsal horn 2. Crosses Anterior White Commissure to contralateral side 3. Ascends through Anterior spinocerebellar tract 4. Enters cerebellum through superior cerebellar peduncle 5. Crosses back to ipsilateral side

Where do the posterior spinocerebellar and cuneocerebellar tracts enter the cerebellum?

Inferior cerebellar peduncle

Afferents from what enter the cerebellar cortex via the middle cerebellar peduncle?

Pontine Nuclei

Afferents from what structures enter the cerebellar cortex via the inferior cerebellar peduncle?

Inferior olive Spinal cord Vestibular nuclei

The efferents of the deep cerebellar nuclei mainly pass through what structure?

Superior cerebellar peduncle

What are the interposed nuclei?

Globose and Emboliform nuclei

Where would the lesion be if the patient was unable to tandem walk?

Vestibulocerebellum | (Also probably spinocerebellum)

Patient is seen sitting in his bed, appears to be shaking and is unable to sit still. Upon examination, he has nystagmus and is unable to walk with one foot in front of the other. Where is his lesion?

Vestibulocerebellum

Disease in what structures can cause midline ataxia?

Vestibulocerebellum Spinocerebellum

Patient is asked to walk around the room and appears to have a wide stance and staggering gait. Normal eye exam and has normal speech. Where is his lesion?

Spinocerebellum

What is dysdiadochokinesia?

Inability to rapidly alternate movements

What is dysmetria?

Inability to accurately move an intended distance

What is an action tremor?

Intention tremor: shaking of the limb during voluntary movement, especially at the end of the movement

Upon a patient examination, he tells you the history with slow, poorly articulated speech. He is unable to rapidly flip his hands back and forth, and appears shaky when touching his nose and then your finger. What disorder is this? Where is the lesion located?

Appendicular ataxia Cerebrocerebellum

A positive Romberg test with eyes open and closed is indicative of what disorder?

Cerebellar ataxia

What is the difference between cerebellar and sensory ataxia?

**Cerebellar**: normal vibration, proprioception, and ankle reflexes, + romberg with both eyes open and closed **Sensory:** abnormal vibration, proprioception, ankle reflexes, +romberg only with eyes closed

How do you test vestibulocerebellum and spinocerebellum?

Station Walking Tandem gait

How do you test cerebrocerebellum?

Rapid alternating movements Finger-to-nose Toe-to-finger Heel-to-shin Rebound and check reflex Speech