Cerebellum

Question 1

Vermis and Paravermian portions of cerebellum

Answer 1

control axial musculature (neck and trunk muscles)

Question 2

Lateral hemispheres of cerebellum

Answer 2

control limb musculature

Question 3

Flocculonodular lobe

Answer 3

• maintains balance

- coordinates head and eye movements with vestibular system

Question 4

Deep cerebellar nuclei

Answer 4

relay point for efferents from cerebellum to other brain regions; include Dentate, Interpositus (Globose + Emboliform), Fastigial nuclei

Question 5

Dentate nucleus

Answer 5

• receives input from lateral cerebellar hemispheres

- projects to thalamus

Question 6

Interpositus nucleui

Answer 6

(= Globose and Emboliform)

• receive inputs from paravermal zones
• projects to red nucleus

Question 7

Fastigial nucleus

Answer 7

• receives input from vermis

- projects to vestibular nuclei and reticular formation (bilaterally)

Question 8

Superior Cerebellar peduncle

Answer 8

• afferents: anterior/ventral SCT, acoustic and optic information
• efferents: (to forebrain) dentato-rubro-thalamic (to Red nucleus) and dentato-thalamic (to thalamus) tracts

Question 9

Middle Cerebellar peduncle

Answer 9

• afferents: pontocerebellar tract (from contralateral cortex)
• efferents: none

Question 10

Inferior Cerebellar peduncle

Answer 10

• afferents: vestibulo-cerebellar, olivo-cerebellar, posterior spinocerebellar tracts
• efferents: cerebellovestibular and cerebelloolivary tracts

Question 11

Layers of Cerebellar cortex

Answer 11

1. Molecular - outermost, basket and stellate cells
2. Purkinje cell layer - purkinje cell bodies
3. Granular layer - granule and golgi cells
4. White matter - tracts/projections

Question 12

Input to cerebellum from outside cerebellum

Answer 12

1. Climbing fibers (excitatory) –> Purkinje cells

2. Mossy fibers (excitatory) –> Granule and Golgi cells (in cerebellar glomeruli)

Question 13

Modulators of Purkinje cells

Answer 13

1. Granule cells (excitatory; pass along modified information they get from mossy fibers)
2. Basket/Stellate cells have inhibitory effect on Purkinjes

Question 14

Vestibulocerebellum

Answer 14

• afferents from ispi vestibular nuclei in brainstem via inferior peduncle to FN lobe and inferior paravermal area
• efferents to fastigial nucleus which then projects to bilateral vestibular nuclei and reticular formation
• functions to coordinate eye, head, neck movements, and maintain body balance

Question 15

Spinocerebellum

Answer 15

• receives the dorsal SCT via inferior peduncle
• also, spinal border cells send copy of LMN’s via ventral SCT (via superior peduncle)
• inferior olive provides information on the contralateral limb
• truncal movements processed in vermis, output via fastigial nucleus to rubrospinal, vestibulospinal, reticulospinal tracts
• limb movements processed in anterior lobe (L lobe = L limbs), sent to EG nuclei, VL of thalamus, M1, CST

Question 16

Cerebrocerebellum

Answer 16

• comprises lateral posterior lobes
• input from pontine nuclei (via MCP)
• output via dentate to red nucleus to VL thalamus (also direct dentato-thalamic output), then to M1
• needed for hand-eye coordination to reach/manipulate an object, as well as automaticity of aspects of cognition as well as fluidity of language

Question 17

Clinical signs of cerebellar dysfunction

Answer 17

• unstable gait, wide stance
• jerky movements, intention tremor
• ataxia of trunk/limbs
• dysmetria of movements
• eye movement disorders, i.e., nystagmus, saccadic/smooth pursuit dysmetria
• speech disorders, i.e., ataxia dysarthria, difficulty with rhythm and intonation