Cerebellum Flashcards
The cerebellum receives ___________ and ____________ information continulously
motor and sensory
3 cerebellar diseases and disorders
- ataxia (incoordination of movements without paralysis)
- hypotonia (decreased muscle tone)
- intention tremors ( loss of muscle synergy)
4 main functions of the cerebellum
- compare actual and intended movements
- planning sequential movements
- learning coordinated movements
- produce a synergy of movements
3 lobes of the cerebellum
- anterior lobe
- posterior lobe
- flocculonodular lobe
Mossy fibers are axons that make up these 4 structures
- cortico-ponto-cerebellar tract
- dorsal/ventral spinocerebellar tract
- spinocuneocerebellar tract and rostral spinocerebellar tract
- vestibular nerve
Which cerebellar peduncle is mainly an “output pathway”?
Superior cerebellar peduncle
What part of the cerebellar peduncle includes input and output pathways?
inferior cerebellar peduncle
the middle cerebellar peduncle has mainly what type of axons?
input pathway axons
2 types of input fibers
- mossy fibers
2. climbing fibers
cortico-ponto-cerebellar tract begins/ends where, via, function
Begins in the Pons
Ends in the cerebellum via the middle cerebellar peduncle
receives input from cerebrum bring to cerebellum
3 layers of cerebellar cortex and cell types
- Molecular layer ( stellate, basket, parallel fibers, dendrites of Purkinje cells)
- Purkinje cell layer
- Granular cell layer (granule, golgi, glomerulus)
3 functionally significant regions
- vestibulocerebellum
- spinocerebellum
- cerebrocerebellum
Vestibulocerebellum location
Flocculonodolar lobe
Vestibulocerebellum input
inner ear and visual systems via the inferior cerebellar peduncle
Vestibulocerebellum output
vestibular nuclei via fastigial nucleus through the superior and inferior cerebellar peduncle
Vestibulocerebellum functions (3)
- equilibrium/balance
- coordinates eye/head movements
- upright posture
Spinocerebellum (intermediate region) location
Vermis
Spinocerebellum input
via superior and inferior cerebellar peduncle
Spinocerebellum output
reticular formation and contralateral thalamus/ red nucleus
via superior cerebellar peduncle (Globose/emboliform)
Spinocerebellum functions (2)
- modulation/control
2. muscle tone
cerebrocerebellum location
lateral cerebellar cortices
cerebrocerebellum input
cerebral cortex via middle cerebellar peduncle
cerebrocerebellum output
contralateral thalamus
via dentate through superior cerebellar peduncle
cerebrocerebellum function
formulation/initiation of movement
floppy loose jointed rag doll appearance (appears inebriated)
hypotonia
loss of balance (gait and trunk dystaxia)
diseequilibrium
loss of coordinatied muscle activity
dyssynergia
difficulty speaking, slurred/scanning speech
dysarthria
lack of coordination of voluntary movement (appendicular)
dystaxia (ataxia)
inability to arrest muscular movement at the desired point
dysmetria
intention tremor
occurs during voluntaty movement (type of dysmetria) gets worse as subject approaches target
inability to perform rapid alternating movements
dysdiadochokinesia
form of dystaxia consisting of to and fro eye movements
nystagmus
consists of breaking down a smooth muscle act into a number of jerky awkward component parts
decomposition of movement
lack of check, inabilty to adjust to changes in muscle tension
rebound
“fatal gastroenteritis”
nausea and vomiting
dorsal/ventral spinocerebellar tracts begin/end/via/function
begin in spinal cord (clarkes column)
end in cerebellum via inferior or superior peduncle
bring input from peripheral proprioceptors in trunk/lower extremities
spinocuneocerebellar tract and rostral spinocerebellar track begin/end/via/function
begin in cuneate nuclei
end in cerebellum via inferior cerebellar peduncle
OR
begin in cervical spinal cord
end in cerebellum via inferior AND superior cerebellar peduncles
function peripheral proprioreceptors upper trunk/ upper extremities
vestibular nerve enters cerebellum via
inferior cerebellar peduncle
climbing fibers arise
inferior olivary nucleus
climbing fibers function
error correction/timing of motor tasks
climbing fibers input
cortex, basal ganglia, red nucleus, other extrapyramidal pathways
climbing fibers enter cerebellum via
inferior cerebellar peduncle
