11.2 Cerebellum

Question 1

What are the main functions of the cerebellum?

Answer 1

Maintain synergy of movement
Maintain upright posture
Monitor and maintain muscle tone

Question 2

What is the general circuit of the cerebellum?

Answer 2

Input from motor cortex via cortico-pontine and ponto-cerebellar pathways
Gets feedback from the peripheral muscles via the spino-cerebellar tracts
Informs the control centres about adjustments needed to carry out the required movement accurately

Question 3

What are the 3 lobes of the cerebellum?

Answer 3

Anterior: most superior surface
Posterior: most of the inferior surface
Flocculonodular: discrete region at the anterior inferior surface

Question 4

What are the deep nuclei of the cerebellum?

Answer 4

Dentate: largest, lateral, convoluted, feedsback to motor cortical areas
Globose and Emboliform (interposed): middle, functions associated with spino-cerebellar feedback
Fastgial: adjacent to midline and functions associated with the vestibular system

Question 5

How do fibres enter the cerebellum?

Answer 5

Fibres from the pons through the middle cerebellar peduncle

Any fibres from below the brainstem through inferior cerebellar peduncle

Question 6

Where do the cerebro-cerebellum, spinocerebellum and vestibulo-cerebell

Answer 6

Cuneo-cerebellum - dentate nucleus - UMN/premotor cortex

Spinocerebellum - interposed nuclei - UMN, motor Cx and brainstem

Vestibulo-cerebellum - fastigial nuclei - vestibular nuclei - LMN

Question 7

What tract makes the climbing fibres?

Answer 7

Olivo-cerebellar

Question 8

What are the mossy fibres and which side do they terminate?

Answer 8

Ponto-cerebellar (C/L
Reticulo-cerebellar (I/L)
Vestibulo-cerebellar (I/L)
Spino and Cuneo-cerebellar (I/L)

Question 9

What is the output to the cortex from the cerebellum?

Answer 9

From the deep nuclei to the thalamus via the superior colliculus and red nucleus

Question 10

What is the output to the spinal cord from the cerebellum?

Answer 10

From the fastigial and interposed nuclei to the superior colliculus, reticular formation and vestibular nuclei to the LMN in medial and ventral horn

Question 11

What information does the superior colliculus receive?

Answer 11

C/L information from the dentate

I/L from vestibular

Question 12

Will will everything going through the superior cerebellar peduncle do and what are the afferents and efferents here?

Answer 12

CROSS
Afferents: ventral spino cerebellar (from mechanoreceptors in the trunk and lower limb)
Efferent: cerebellar terminals in the thalamus map

Question 13

What runs through the middle cerebellar peduncles?

Answer 13

ONLY AFFERENTS

Ponto cerebellar fibres

Question 14

What can a pons lesion cause?

Answer 14

Cerebellar signs due to the crossing of the pontocerebellar fibres

Question 15

What runs in the inferior cerebellar peduncle?

Answer 15

Afferents: dorsal spino-cerebellar tract fibres, cuneo-cerebellar tract fibres
Efferent: fastigial nerve

Question 16

What is the role of the red nucleus and what is its inputs and outputs?

Answer 16

Gets input from the red nucleus and sends axons to the C/L cerebellar cortex of the anterior and posterior lobes (olivo-cerebellar) as the climbing fibres
Acts to modify the motor response, especially during learning and tweaks the output to minimise errors

Question 17

Where do the climbing fibres come from and what is their role?

Answer 17

Have their cell bodies in the inferior olivary nucleus which gets inputs from the red nucleus
They excite single purkinje fibres and send collaterals to the deep nuclei to provide information

Question 18

What is the typical cerebellar circuit?

Answer 18

Mossy fibres come in, synapse with granule cell and then onto purkinje cell

Climbing fibres synapse directly onto purkinje fibres

Other cells in the system (Golgi and deep cerebellar nuclei) provide feedback and information comparing what was supposed to happen and what actually did happen onto the purkinje cells