cerebellum Flashcards
name the 3 lobes of the cerebellum
anterior
posterior
flocculonodular
what % of brain mass and brain neurons does the cerebellum take up ?
10.3% brain mass
80.2% brain neurons
what are the 4 main functions of the cerebellum
movement coordination
maintenance of posture
maintenance of muscle ton/balance
motor learning
where is the cerebellum located ?
posterior of the brainstem
why Is cerebellum location ideal for motor learning ?
integrates sensory and motor inputs
what is cerebellar hypoplasia ?
cerebellum underdeveloped
tremors
coordination struggles
what is cerebellar ataxia ?
abnormal execution of multi-jointed movements - lack of coordination
caused by stroke, MS, tumours ,etc
struggles eye tracking
cerebellum is connected to brainstem by 3 pairs of peduncles - name them
superior
middle
inferior
what occurs in the superior peduncle ?
no inputs
outputs to motor cortex via thalamus and red nucleus
what occurs in the middle peduncle ?
inputs from motor cortex via PONS
no outputs
what occurs in the inferior peduncle ?
inputs from inferior olivary nucleus, spinal chord and vestibular nuclei
outputs to reticular formation(brainstem), spinal cord and vestibular nuclei
what are the 3 functional subdivisions of the cerebellar cortex ?
cerebrocerebellum
spinocerebellum
vestibulocerebellum
what happens in the cerebrocerebellum ?
involved in motor planning
input :
pons , from motor cortex
inferior olive from motor cortex (via red nucleus) and spinal cord
output :
dentate nucleus to motor cortex
what happens in the spinocerebellum ?
compromises the vermis and intermediate cortex
regulates body movements
somatic sensory inputs exhibit somatotopy
what are the inputs in the spinocerebellum ?
vermis - spinal cord carrying sensory info from trunk + head
intermediate cortex - spinal cord carrying sensory info from the limbs
what are the outputs in the spinocerebellum ?
vermis- fastigial nucleus to medial descending reticuluospinal and vestibulospinal tracts
motor execution
intermediate cortex - interposed nucleus to lateral descending corticospinal and rubrospinal tracts
motor planning
what is the vestibulocerebellum also known as ?
focculonodular lobe
what does the vestibulocerebellum regulate ?
balance and eye movements
what are the inputs of the vestibulocerebellum ?
vestibular nucleus from semicircular canals and otolith organs
what are the outputs of the vestibulocerebellum ?
vestibular nucleus to axial and proximal muscles, limb extensor and head/eye muscles
name the elements of the deep cerebellar nuclei from lateral to medial
dentate - output to motor cortex via superior peduncle and thalamus
interposed - output to red nucleus via sup peduncle
fastigial - output to brainstem and vestibular nucleus via inferior peduncle
what are the 5 principle elements of cerebellar circuitry ?
mossy fibres
granule fibres
climbing fibres
prukinje fibres
parallel fibres
name key elements of purkinje fibres
cell body and vast dendritic tree
receive afferent input from parallel and climbing fibres
40:1 input:output ratio
function is inhibitory
what is function of mossy fibres in cerebellar circuitry ?
primary neurons that carry info to cerebellum
what is function of granule cells in cerebellar circuitry ?
attach to parallel fibres which synapse with dendrites of purkinje cells
what happens when purkinjie cells become activated in cerebellar circuitry ?
purkinje cells inhibit cerebellar nuclei
modulating motor output
