Cerebellum & Movement

Question 1

What are the functions of the cerebellum?

Answer 1

Voluntary movement coordination, error detection, balance, muscle tone, maybe cognition

Question 2

What are the functions of the spino, ponto, and vestibulocerebellum?

Answer 2

S: unconscious proprioception, error detection
P: coordination of intended movements
V: balance, eye movements, posture

Question 3

What parts of the cerebellum are spinocerebellum?

Answer 3

Anterior lobe, vermal and paravermal areas of posterior lobe

Question 4

What parts of cerebellum are pontocerebellum?

Answer 4

Posterior lobe lateral hemisphere

Question 5

What parts of cerebellum are vestibulocerebellum?

Answer 5

Flocculonodular lobe

Question 6

What runs in the superior cerebellar peduncle?

Answer 6

Mostly efferent fibers, some afferent from ventral spinocerebellar tract

Question 7

What runs in the middle cerebellar peduncle?

Answer 7

Afferent fibers contra pontine gray: indirect cortical input from lateral hemisphere post parietal (planning) & motor association cx (executing mvmt)

Question 8

What runs in the inferior cerebellar peduncle?

Answer 8

Afferent fibers from Clark & acc cun nuc to spinocerebellum, contra ION to entire cerebellum, vest n and nuc to vestibulo; some efferents

Question 9

What are the afferent inputs to vestibulo, spino, and ponto/cerebrocerebellum?

Answer 9

V: vestibulocerebellar tract, ION
S: spinocerebellar trx, pontocerebellar trx, ION
P: ponto trx and ION

Question 10

What are the input fibers to cerebellum?

Answer 10

Climbing fibers from ION, mossy fibers

Question 11

What are the internal circuitry fibers of cerebellum?

Answer 11

Climbing fibers to Purkinje, mossy fibers to granule cells to Purkinje, and interneurons (stellate, basket, Golgi cells)

Question 12

What are the output fibers of the cerebellum?

Answer 12

Purkinje cells to deep nucleus

Question 13

Describe the climbing fibers.

Answer 13

Excitatory fibers from ION, via inferior cerebellar peduncle. Activated when errors are made (to correct), synapse on Purkinje dendrites

Question 14

Describe mossy fibers.

Answer 14

Excitatory. Make up all other cerebellar afferents through all peduncles. Synapse on granule cell bodies and dendrites.

Question 15

What is the granular layer?

Answer 15

Innermost, with granule cells: small excitatory cells, most cells in cerebellar cortex, input from mossy fibers, output to parallel fibers (to molecular layer). Also has Golgi cells (inh to granule cells)

Question 16

What is the Purkinje layer?

Answer 16

Middle layer with Purkinje cells: inhibitory, at 90’ to parallel fibers, input from climbing and parallel, output to deep nuclei (main output of cerebellum)

Question 17

What is the molecular layer?

Answer 17

Outermost, few stellate and basket cells (inh). Primarily axons (parallel, climbing) and dendrites (Golgi, Purkinje)

Question 18

What are the deep nuclei? Where are they located?

Answer 18

Dentate (lateral), interpositus (emboliform + globus), fastigial (medial); excitatory output, at level of PM junction

Question 19

What is input to and output from dentate nucleus?

Answer 19

In: lateral hemisphere Purkinje cells (ION climbing, ponto mossy from post parietal)
Out: superior cerebellar peduncle

Question 20

What is input to and output from interpositus nucleus?

Answer 20

In: paravermal Purkinje (ION climbing, ponto mossy from M1, spinocerebellar mossy proprio)
Out: superior cerebellar peduncle

Question 21

What is input to and output from fastigial nucleus?

Answer 21

In: vermal Purkinje (ION climbing, spino mossy proprio)
Out: sup and inf cerebellar peduncles

Question 22

What is input to and output from vestibular nuclei?

Answer 22

In: F-N lobe P cells via ICP (ION climbing, vestibular mossy)
Out: MLF

Question 23

What efferent fibers are in superior cerebellar peduncle?

Answer 23

Deep nuc to contra red nuc (interpos nuc) to SC, VL/VA thalamus to premotor area (dentate) and M1 (interpos), vestibular nuc/RF to SC (fastigial)

Question 24

What efferent fibers are in inferior cerebellar peduncle?

Answer 24

Fast nuc -> ipsi vest nuc and RF
FN Purkinje (inh) to ipsi vest nuc (up to CN 3,4,6, down to vestibulospinal trx)

Question 25

What are the four cardinal cerebellar signs?

Answer 25

Ataxia, intention tremor, hypotonia, asthenia (weakness)

Question 26

What are causes of unilateral cerebellar signs? Bilateral?

Answer 26

Uni: tumor, infarct, trauma, demyelinating disease
Bi: toxic effects, metabolic/nutritional problems, MS

Question 27

What is posterior lobe syndrome? What are possible causes?

Answer 27

Loss of voluntary mvmt coordination: intention tremor, dysmetria, dysdiadochokinesia, maybe dysarthria
From stroke, trauma, degen disease

Question 28

What is anterior lobe syndrome? What are possible causes?

Answer 28

Loss of LL coordination: gait ataxia, impaired heel-shin, progresses to UL and dysarthria
From malnutrition, chronic alcoholism

Question 29

What is flocculonodular lobe syndrome? What are possible causes?

Answer 29

Loss of paraxial mm coordination: truncal ataxia, falling while trying to sit/stand, instability head/neck coord/titubation, nystagmus
From tumor (medulloblastoma)

Question 30

What other functions has cerebellum been controversially linked to?

Answer 30

Higher cognition, emotion/limbic system, attention

Question 31

What deficits appear with lesions to anterior, posterior, medial, and lateral cerebellum?

Answer 31

Ant: motor
Post: cognition
Med: affective/emotion
Lat: cognition

Question 32

What are cognitive affective disorders associated with cerebellum lesions?

Answer 32

Executive function (planning, verbal fluency, reasoning, working memory), spatial cognition, language deficits, personality change (blunted or disinhibited)

Question 33

What are symptoms of midline cerebellar tumor?

Answer 33

Flat affect, inappropriate behavior, perseveration, difficulty making decisions