L45 Movement Disorders Cerebellum Flashcards
what are the functions of the cerebellum?
synergy of movement
posture
fine tunes movement!
what is synergy of movement?
many elements of muscular contraction are collectively coordinated to create purposeful movement (walking etc.)
what is posture
the body is orientated appropriately relative to the vector of gravity - dictated by muscle tone
the cerebellum acts as a ____
comparator
- receives copies of motor instructions that were already sent to LMN
- compares sensory feedback to original motor instructions
- errors are reported back to motor centers
the cerebellum regulates ___body
ipsilateral
acute cerebellar damage often yields ______
pronounced motor deficits (ipsilaterally)
substantial functional recovery may occur in _____
chronic, but non-progressive cerebellar damage
what separates the anterior lobe from the posterior lobe?
primary fissure
what CN are sort of associated with the flocculo-nodular lobe of the cerebellum
CN 7 and 8
more medial structures of the cerebellum regulate ___
trunk
more lateral structures of the cerebellum regulate ___
limbs
describe the flocculonodular lobe/vestibulo-cerebellum
think equilibrium!
afferents from vestibular apparatus (balance, eye movements)
works with CN 8
describe the spino-cerebellum/anterior lobe?
sensory feedback (trunk and limb movement)
describe the cerebro-cerebellum/posterior lobe?
integrates motor with sensory feedback (precise movements - location and timing, planning)
receives afferent connections from the deep pontine nuclei
superior cerebellar peduncle carries what and where is it
efferents
cerebellum to midbrain and pons
middle cerebellar peduncle carries what and where is it
afferent
pons to cerebellum
inferior cerebellar peduncle carries what and where is it
afferent ( + many efferents)
spinal cord and medulla to cerebellum
what is similar between the cortex and cerebellum
from outside:
gray, white, gray, ventricles
how many layers does the cerebellum have? what are their names
3
molecular layer
purkinje layer
granule layer
what does the vermis and flocculonodular lobe communicate with
fastigial nuclei –> vestibular system
what does the paravermis communicate with?
interposed nuclei –> red nucleus
what does the lateral hemispheres communicate with?
dentate nuclei –> thalamus
what are sx/sx associated with vestibule-cerebellum/flocculonodular lobe lesions?
affect equilibrium related motor functions
- nystagmus (ocular ataxia)
- tilted head
- titubation (head-nodding)
- truncal ataxia (imbalance) with compensatory wide-based stance – impaired tandem walking
what are sx/sx associated with spino-cerebellum/anteiror lobe lesions?
affect posture and movement of limbs
- ataxias of the limbs common (ipsilateral)
- gait ataxia accompanies by lurching to the side of the lesion
what are sx/sx associated with cerebro-cerebellum/posterior lobe lesions?
affect accuracy and timing of movement
- ataxia
- decomp of movement
- dysarthia (slurred monotonous speech)
- dyssynergia (uncoordinated limbs)
- dysdiadokinesia - inability to perform rapidly alternating movenets
- dysmetria - past pointing
- intention tremor
- hypotonia
- rebound phenomenon
in what population do midline astrocytomas most commonly occur in?
children
what are the motor signs of tumors?
- nystagmus
- truncal ataxia
- broad-based stance with impaired tandem walking
- hypotonia
what are other manefestations of tumors?
- headache
- hydrocephalus
- intracranial pressure elevated - papilledema
- nausea and vomiting
what arterial system is implicated in cerebellar stroke?
vertebral
unilateral occlusive disease is common
what are the motor signs of cerebellar stroke
- dysarthia
- dyssynergia (ipsilateral)
- dysmetria
- dysdiadokinesia
- intension tremor (ipsilateral)
- rebound phenomenon (ipsilateral)
- limb ataxia (ipsiateral)
- truncal ataxia
brainstem signs are not uncommon - cerebellar arteries supply the brainstem en route to the cerebellum!
what is vitamin B1 (thiamin) deficiency linked to
degeneration of the rostral vermis and adjacent parts of the remaining anterior cerebellar lobe
cortical purkinje cells degenerate
motor signs involve leg and trunk
some resolution may follow abstinence and diet supplementation
alcoholics at higher risk
describe louis-bar syndrome
autosomal recessive
widespread degeneration fo cerebellar purkinje cells and compromised immune function (chromosome 11)
what are sx/sx of louis-bar syndrome?
delayed development of motor skills accompanies increased vulnerability to infection
- most obvious related to walking, talking, facial and ocular movements
- long term: heightened sensitivity to ionizing radiation is observed along with increased vulnerability to cancers
- skin and eyes tend to express small dilated blood vessels
describe cerebellar cognitive affective syndrome (CCAS)
lesions of the posteiror lobe are considered to correlate with dysfunctional cognitive and emotional systems
-leads to:
emotional blunting and depression
disinhibition
psychosis
executive, visual-spatial and linguistic deterioration
condition is conceptualized in relation to “dysmetria of thought”
what are the two fiber inputs of the cerebellar cortex?
climbing fibers
mossy fibers
what are climbing fibers
input from inferior olivary nucleus
what are mossy fibers?
carry all other inputs
