Cerebellum

Question 1

Where does the anterior lobe receive input from and what is its role?

Answer 1

Input from the spinocerebellar tracts

Regulation of muscle tone

Question 2

Where does the posterior lobe receive input from and what is its role?

Answer 2

Corticopontocerebellar tracts

Coordination of voluntary motor activity

Question 3

Where does the flocculonodular lobe receive input from and what is its role?

Answer 3

Input from the vestibular system

Posture and balance

Question 4

What are some characteristics of the superior cerebellar peduncle?

Answer 4

Major output from cerebellum

Efferents from all three deep cerebellar nuclei tot he regulated the rubrospinal and corticospinal UMN systems

Only peduncle to decussate

Question 5

What is the middle cerebellar peduncle?

Answer 5

Largest cerebellar peduncle and connects to the pons

Carries afferent pontocerebellar fibers to the neocerebellum

Question 6

What is the inferior cerebellar peduncle?

Answer 6

Consists of two divisions - restiform and juxtarestiform bodies

Involved in the reticular and vestibular systems

Question 7

What are the three major cellular layers of the cerebellum?

Answer 7

Granule cell layer - small and tightly packed layer of excitatory interneurons

Purkinje cell layer - purkinje cell bodies

Molecular cell layer - majority of synapses are made here

Question 8

What are the two cerebellar inputs?

Answer 8

Mossy Fibers - excitatory neurons that ascend through the white matter and synapse onto granule cell dendrites

Climbing fibers - Project from the contralateral inferior olivary nucleus, excitatory, dampen purkinje response to input from parallel fibers

Question 9

What cell is the output from the cerebellum?

Answer 9

Purkinje cells

Question 10

What are basket cells and stellate cells?

Answer 10

Inhibitory neurons that reside in the mollecular layer and synapse onto purkinje cells

Receive input from parallel fibers and promote lateral inhibition of adjacent purkinje cells

Question 11

What are golgi cells?

Answer 11

Reside in the granule cell layer, but project dendrites to the molecular layer to synapse with parallel fibers

Golgi cells then synapse on granule cells, providing a system of feedback inhibition to granule cells

Question 12

What are the dentate nuclei?

Answer 12

Largest deep cerebellar nuclei, in lateral hemisphere

Projects to the red nucleus, VL, and inferior olivary nucleus

Involved in initiation, planning, timing of volitional movement

Question 13

What are the Emboliform and Globose nuclei?

Answer 13

Interposed nuclei, within intermediate hemisphere

Outputs relayed via the VL to the corticospinal tract regulating distal muscles

Outputs to the red nucleus to give rise to the crossed rubrospinal tract

Question 14

What are the fastigial nuclei?

Answer 14

Input from vermis and flocculonodular lobe

Output to VL, tectum, and superior cerebellar peduncle

Involved in muscle tone and posture via vestibulospinal tract

Question 15

What are the vestibular nuclei?

Answer 15

NOT deep nuclei

Output to medial longitudinal fasciculus and juxarestiform body

Question 16

Describe corticopontine input to the cerebellum

Answer 16

Pontocerebellar fibers enter the middle cerebellar peduncle and relay information via mossy fiber projections to the entire cerebellum, except the nodulus

Question 17

Describe spinocerebellar input

Answer 17

Dorsal - lower extremity, trunk. Inferior peduncle mossy fibers

Cuneo - upper extremity, trunk. inferior peduncle, mossy fibers

Ventral - coordination of posture and lower limb movement, superior peduncle, double crossed

Question 18

Describe inferior olivary nuclear complex input

Answer 18

Olivocerebellar fibers decussate before entering the inferior cerebellar peduncle

Information conveyed via climbing fibers to reach the contralateral cerebellum

Question 19

Describe the function of the lateral cerebellar hemisphere

Answer 19

Projects to dentate nucleus, then to contralateral VL of thalamus

Then projects to lateral CS tract and parvocellular red nucleus

Question 20

Describe the function of the intermediate/paramedian hemisphere

Answer 20

Project to the emboliform and globose nuclei then to contralateral VL and red nucleus

Continue to lateral CS tract and rubrospinal tract

Question 21

Describe the function of the vermal/median zone

Answer 21

Projects to the fastigial nucleus, then to the VL

From there, to the anterior CS tract

Also project to the uncinate fasciculus to the vestibular nuclei

Question 22

Describe the function of the flocculonodular lobe/vestibulocerebellum

Answer 22

Vestibvular nuclei/ganglia project to the ipsilateral flocculonodular lobe

Direct reciprocal connections are unique in the cerebellum

Out put to the medial longitudinal fasciculus provides ocular control

Question 23

What vasculature provides blood supply to the cerebellum?

Answer 23

Posterior inferior cerebellar artery

Anterior inferior cerebellar artery

Superior cerebellar artery

Question 24

What are the symptoms of a cerebellar hemisphere lesion?

Answer 24

Ataxia towards lesion

Hypotonia, dysmetria, intention tremor, dysdiadochokinesis

Ipsilateral to lesion

Question 25

What are the symptoms of a vermis lesion?

Answer 25

Affects Medial motor system

Truncal ataxia

Dysarthria, ocular ataxia and nystagmus

Question 26

What can cause false localization of ataxia?

Answer 26

Lesions in the peduncles or pons can produce ataxia without direct cerebellar involvement

Question 27

What is Friedreich’s ataxia?

Answer 27

Autosomal recessive neurodegenerative disorder that targets dorsal and lateral columns, can involve cerebellar peduncles

Ataxia, areflexia, impaired dorsal/medial lemniscal symptoms, progressive weakness with babinski

Question 28

What is Wernicke’s encephalopathy?

Answer 28

Irreversible neuronal degeneration (Wernicke-Korsakoff syndrome)

Caused by B1 deficiency/alcoholism

Symptom triad: Cognitive dysfunction, gait ataxia, and nystagmus