Cerebellum

Question 0

Function of cerebellum

Answer 0

To detect motor error between intended movement and actual movement and reduce this error

Question 1

How does cerebellum influence movement

Answer 1

By modifying activity of UMNs (like BG)

Question 2

Grey matter structures in cerebellum

Answer 2

Cerebellar cortex: input

Deep nuclei: input and output

Question 3

Parts of cerebellum

Answer 3

Cerebrocerebellum: regulation of highly skilled movements. Planning of complex sequences of movements
Spinocerebellum: lat part movements of distal muscles. Med part movement of proximal muscles. Regulates eye movements
Vestibulocerebellum: gets input from vestibular nucli. Regulation of movements underlying posture and VOR reflex

Question 4

Connections to cerebellum

Answer 4

To other parts of the nervous system via the superior, middle and inferior cerebellar peduncles

Question 5

Superior peduncle

Answer 5

Almost entirely afferent from deep cerebllar nuclei.

Axons project to superior colliculi, after relaying in thalamus, primary motor and premotor

Question 6

Middle cerebellar peduncle

Answer 6

Afferent from pontine nuclei which receives info from wide range of cerebral cortex areas and superior colliculi

Question 7

Inferior cerebllear peduncle

Answer 7

Multiple afferent and efferents
Afferent from vestibular nuclei
Efferent to vestibular nuclei and reticular formation

Question 8

Cerebellar modulatory input

Answer 8

From inferior olive and locus ceruleus in brainstem

Nuclei participate in learning and memory functions seved by cerebellar activity

Question 9

Where does cerebellar cortex project to

Answer 9

Deep cerebellar nuclei

And vestibular complex

Question 10

Major deep nuclei on each hemisphere

Answer 10

• dentate nucleus (cerebrocerebellum)
• two interposed nuclei: globose and emboliform (spinocerebellum)
• fastigial nucleus (spinocerebellum)
• vestibular nuclei (vestibulocerebellum)

Question 11

Dentate nucleus

Answer 11

Gets afferent from cerebrocerebellum
Efferents destined for premotor and cortices of frontal lobe
Planning voliational movements

Question 12

Dentate nucleus pathway

Answer 12

• fibres exit via superior cerebellar peduncle
• first relayed in ventral nuclear complex of thalamus
• cross midline and ascend contralateral hemisphere

Gives out fibres to red nucleus which projects to inferior olive. Feedback mechanism

Question 13

Fastigial nuclei

Answer 13

Project from spinocerebellum
Project via inferior cerebellar peduncle
Goes to reticular formation and vestibular complex
Governs axial and proximal limb musculature

Question 14

Interposed nuclei

Answer 14

Project via superior cerebellar peduncle
To thalamic circuits that interact with motor regions of frontal lobe for voliational movements
Also project to contralateral superior colliculus

Question 15

Vestibular nuclei

Answer 15

Via inferior peduncle
Termonate in nuclei of vestibular complex
Movements of head, eyes, neck for linear accell

Question 16

Afferents from pontine nuclei

1

Answer 16

Pontine nuclei get afferent fibres from cortex and relay to contralateral cerebellar cortex
Axons from pontine nuclei are MOSSY fibres
These synapse on neurones in deep cerebellar nuclei and on granule cells in granule layer of cerebellar cortex

Question 17

Afferents from pontine nucle2

Answer 17

Granule cells give rise to parallel fibres that ascend to molecular layer of cerebllar cotex
Parallel fibres bifurcate in molecular layer. Relay onto dendritic spines of purkinje fibres

Question 18

Afferents from pontine nuclei

3 purkinjes

Answer 18

Purkinje cell bodies in purkinje layer
Also get modulatory inputs from climbing fibres (come from inf olive) that synapse onto their shafts
Purkinjes project to deep cerebellar nuclei
Are GABAergic so oversall output of cerebellar cortex is inhibitory

Question 19

2 stages of cerebellar processing

Answer 19

EXCITATORY LOOP

INHIBTIROY LOOP

Question 20

Excitatory loop

Answer 20

Mossy fibres and climbing fibres drive activation of deep cerebellar nuclei

Question 21

Inhibitory loop

Answer 21

Inhibitory purkinje fibres modulate activity of deep nuclei by responding to excitatory signals of parallel fibres to generate inhibitory output

Question 22

Cerebellar damage

Answer 22

Persistent errors of movement on ipsilateral side

Question 23

Alcohol on cerebellum

Answer 23

Degen of ant portion of cerebellar cortex
Affects spinocerebellum, affecting movement of lower limbs
Wide staggering gait

Question 24

Damage to vestibulocerebellum

Answer 24

Impaired ability to stand up and maintain direction of gaze

Eyes cant fixate - nystagmus