Unit 3 - cerebellum

cerebellum is responsible for fine tuning what kind of movements

simple motor tasks, complex motor tasks, highly specialized tasks

cerebellum is responsible for learning via

long term depression and potentiation

cerebellum does not connect to

UMN or LMN at all - modulates but does not cause movement

all cerebellar functions are

nonconscious

primary information entering cerebellum is

sensory

cerebellum lesions will always show

ipsilateral effects

an intact cerebellum is necessary for

normal movements and anticipatory movements

three types of movement that cerebellum modulates

equilibrium/balance, gross movements, fine/distal voluntary movements

key role in motor learning and adapatation

compares intended movement with actual movement

intended movement comes from

premotor and supplemental motor areas

actual movement comes from

feedback signals to determine if movement matches - adapts and corrects as necessary

3 sources of cerebellym input

spinal, vestibular and cerebral

spinal input to cerebellum

peripheral proprioceptive input

vestibular input to cerebellum

where your head is in space

cerebral input to cerebellum

input of intended movement

cerebellar output comes from

deep nuclei - dentate, emboliform, globose, fastigial (lateral to medial)

input into cerebellum goes to

cerebellar cortex to be processes

after processing at cerebellar cortex, input projects to

deep nuclei through purkinje cells

deep cerebellar nuclei project

out of cerebellum to influence motor tracts

output of the cerebellum goes through the

superior cerebellar peduncle

superior cerebellar peduncle influences what tracts to modulate movement

vestibulospinal, reticulospinal, rubrospinal, corticospinal, corticobulbar

superior cerebellar peduncle

cerebellum to midbrain, cerebellar efferents/output signals from deep nuclei

middle cerebellar peduncle

cerebellum to pons providing cortical input

inferior cerebellar peduncle

cerebellum to medulla, afferents from SC, vestibular apparatus and inferior olivary nucleus, efferents to vestibular.reticular nuclei (bidirectional)

3 lobes of cerebellum

anterior, posteiror, flocculonodular

vertical division of cerebellym

vermis, paravermis, lateral hemispheres (medial to lateral), each region control a specific type of movment

spinocerebellum

contains vermis and paravermis

spinocerebellum function

extensive connections with spinal cord for sensory information, coordinates gross limb movements with sensory information (anticipatory contractions)

spinocerebellar input is not

consciously perceived

spinocerebellar input gathers mostly

proprioceptive information ipsilaterally

the vermal section of spinocerebellar goes to

motor thalamus and impacts medial motor tract at postural muscles and RetST

fastigial nucleus of spinocerebellar goes to

brainstem nuclei to connect directly to cortex

paravermis of spinocerebellar goes to

lateral motor tracts to control distal muscles

cerebrocerebellum

lateral hemispheres

function of cerebrocerebellum

connects with cerebral cortex via pons and coordinates distal voluntary movements (middle cerebellar peduncle is along same path)

cerebrocerebellum input is from

all four lobes of the brain

paravermal parts of spinocerebellar and cerebrocerebellar tracts both

adjust lateral tracts at distal limb muscles (motor cortex, red nucleus, premotor cortex)

vestibulocerebellum

flocculonodular lobe

function of vestibulocerebellum

receives info from vestibular system and regulates equilibrium, coordinates head and eye movements with respect to gravity, ipsilaterally

medial cerebellar lesion symptoms

ataxia, nystagmus, tremor of head or body

lateral cerebellar lesion symptoms

ataxia, nystagmus, hypotonia, impaired coordination, dysdiaochokinesia, dysmetria

ataxia

all cerebellar lesions, impaired coordination (not weakness)

nystagmus

abnormal eye movements at rest (double vision) (inappropriately thinking the head is turning)

hypotonia is due to

decreased drive to the muscle

dysdiadochokinesia

inability to rapidly alternate movements

dysmetria

improper measuring of distance in muscular acts (finger to nose test), action tremor, rebound phenomenon

UMN signs

paralysis, spasticity/clasped knife, hyperreflexia

LMN signs

paralysis, flaccidity, decreased DTRs, denervation atrophy, fasciculation/fibrillation

basal ganglia signs

dyskinesia, bradykinesia, tremor, rigidity (not spasticity)

cerebellar signs

incoordination, dysmetria, dysdiadochockinesia, rebound phenomenon, hypotonia, ataxia, action tremor