Cerebellum

Question 1

where is the cerebellum located

Answer 1

subcortical structure that is a part of the hind brain

Question 2

what is the concentration of cerebellar neurons

Answer 2

accounts for less than 10% of the brain volume but more than 50% of the neurons in the brain
more than any other area of brain (including cerebral cortex)

Question 3

what is the structure of the cerebellum

Answer 3

composed of 2 hemispheres
receives sensory feedback from the ipsilateral side of the body
feedback transferred to contralateral cortex

Question 4

what is the somatotopy of the cerebellum

Answer 4

fractured somatotopy
- every area of the body is represented by organisation resembles a mosaic
- no continuity with the body
- no homunculus

Question 5

what are the 3 distinct functional areas in the cerebellum

Answer 5

vestibulocerebellum - reflexive eye movements
spinocerebellum - balance and locomotion
cerebrocerebellum - timing and force of voluntary muscle contractions

Question 6

where is the vestibulocerebellum

Answer 6

most anterior (rostral) portion of the cerebellum

Question 7

what is the function of the vestibulocerebellum

Answer 7

governs reflexive eye mvmts following rapid changes in head orientation
- governs posture and balance
- helps with VOR

Question 8

what are the inputs for the vestibulocerebellum

Answer 8

vestibular nuclei and 8th cranial nerve (vestibular afferents)
- transmit info about head orientation from receptors in the inner ear

Question 9

what are the outputs for the vestibulocerebellum

Answer 9

brainstem - to drive reflexive eye mvmts
spinocerebellum - govern standing posture and balance

Question 10

what is the spinocerebellum composed of

Answer 10

cerebellar vermis
intermediate hemispheres

Question 11

which 2 nuclei are present in the spinocerebellum and where

Answer 11

fastigial nucleus - in the vermis
interposed nucleus - in the intermediate hemispheres

Question 12

what are the functions of the spinocerebellum

Answer 12

• controlling locomotion, balance and body posture
• regulating excitation of cortical motor areas
• integration of expected sensory info from efference copy of motor commands with actual sensory feedback

Question 13

what are the inputs for the spinocerebellum

Answer 13

vermis - somatosensory info from spinal cord, visual, and vestibular input, and input from vestibulocerebellum
- controlling locomotion, balance, and posture

intermediate hemispheres - somatosensory info from spinal cord, visual input, efference copy of motor commands from M1 and pre motor areas

Question 14

what are the outputs for the spinocerebellum

Answer 14

fastigial nucleus - controls tone of muscles of the trunk and proximal arm through the brainstem

interposed nuclei - tone of axial and llimb muscles
- projects to M1 and pre motor areas via the thalamus for voluntary mvmts

Question 15

what is the cerebrocerebellum composed of

Answer 15

composed of lateral cerebellar hemipsheres and dentate nucleus

Question 16

what is the function of the cerebrocerebellum

Answer 16

governs planning and online control of goal directed voluntary motor actions

Question 17

what are the inputs to the cerebrocerebellum

Answer 17

interposed nuclei and spinal cord (brainstem) - somatosensory info
M1 and frontal motor areas - planning and intent related activity

Question 18

what is the output from the cerebrocerebellum

Answer 18

controls tone and timing and muscle activity of ipsilateral limbs and muscles of appendicular skeleton via M1 / lateral CST

Question 19

what does the superior cerebellar peduncle (SCP) connect

Answer 19

outputs from the cerebellum to the cerebral cortex
outputs travel from the deep cerebellar nuclei (DCN) to the thalamus (ventro lateral nucleus - VL) to the cerebral cortex
- also brings info fom the anterior spinocerebellar pathways to cerebellar cortex

Question 20

what does the middle cerebellar peduncle (SCP) connect

Answer 20

cerebral cortex info travels to the cerebellum
- provides the DCN with efference copies of descending motor commands

Question 21

what does the inferior cerebellar peduncle (ICP) connect

Answer 21

info from dorsal spinocerebellar pathway travels to cerebellar cortex