Case 7 - Cerebellum and control of movement Flashcards
what do lower motor neurones (spinal cord and brainstem) innervate
skeletal muscle
what do upper motor neurones innervate (cerebral cortex and brainstem)
control lower motor neurones
features of alpha Lower motor neurones
innervate extrafusual muscle fibres - give muscle its strength
what do gamma motor neurones innervate
intrafusual muscle fibres - stretch receptors
what do lower motor neurones mediate (reflexes)
stretch reflex (monosynaptic reflex from stretch receptors to alpha motor neurones)
gamma reflex (controls sensitivity of stretch reflex)
what do lower motor neurone lesions result in
paralysis
loss of tendon reflexes
hypotonia, wasting, fasciculation
motor neurone disease, polio, peripheral nerve injury
symptoms are ipsilateral
stretch reflex and gamma reflex diagram
what type of pathways are upper motor neurones
descending pathways
what influences alpha and gamma motor neurones via these descending tracts
brainstem nuclei (vestibular, reticular, red nuclei)
what do these descending pathways control
control reflexes, tone and posture
what do brainstem nuclei excite
excite gamma motor neurones. brainstem nuclei are inhibited by cerebral cortical efferents (not completely true just a posited theory)
what are the two tracts of upper motto neurones
corticospinal and corticobulbar
what is another name for corticospinal tract
pyramidal
what do these two tracts control
fine skilled movements
corticospinal and corticobulbar tracts diagram
what do upper motor neurone lesions cause
paralysis and positive Babinski reflex due to corticospinal tract damage
hypertonia and hyperreflexia due to loss of cortical inhibition of brainstem nuclei
paralysis, hypereflexia and hypertonia are referred to as spasticity
symptoms are contralateral
the basal ganglia diagram
what does the cerebellum do
coordinates balance and movement
concerned with which muscles need to be activated to achieve a particular movement
integrates information from the cerebral cortex (via pons) and peripheral sense organs
sends output to brainstem nuclei and cerebral cortex (via thalamus)
diagram of the cerebellar peduncles
what is there cerebellum connected to other structures by
3 sets of nerve fibres called cerebellar peduncles
what connects the cerebellum to the medulla
inferior cerebellar peduncle
what connects the cerebellum to the pons
middle cerebellar peduncle
what connects the cerebellum to the midbrain
the superior cerebellar peduncle
what is the paleocerebellum particularly connected with q
the spinocerebellar tract - afferents to the cerebellum from the periphery
what is the largest part of the functional divisions of the cerebellum
the neocerebellum is the largest part and is paeticualry connected to the cerebral cortex via a relay or a connection in the pons
diagram showing the functional divisions of the cerebellum
what are the deep cerebellar nuclei
what is the input into the cerebellum
spinocerebellar tracts
vestibular nuclei
cerebral cortex
where is the vestibular nuclei located
in the medulla oblongata in the brainstem and go trough the medulla at the level of the interior olivary nucleus
what is input by the cerebral cortex via
pontine nuclei that are scattered throughout the tegmentum
where is the output of the cerebellum from and to
from deep cerebellar nuclei
to brainstem and thalamus
where does the purkinje layer lie
between the molecular layer and the granular layer in the cerebral cortex
where does input to the archiceebellum come from
input comes from the vestibular nerve and to the vestibular nuclei and from there via the inferior peduncle cells project into the cerebellar cortex
where do purkinje cells project to
the gastigial nucleus and the gastigial nucleus happens to project back to the vestibular nuclei and it also projects to the reticular nuclei of the brainstem and both of these have connections to the spinal cord
what is the output of purkinje cells to
the deep cerebellar nuclei
connections of the paleocerebellum diagrams
connections and pathways of the neocerebellum diagram
what is the result of a lesion in the cerebellar midline
loss of postural control and balance
what happens if there is a unilateral hemisphere lesion in the cerebellum
incoordination of arm and leg causing unsteady gait. symptoms usually occur ipsilaterally
what happens if there is a bilateral hemisphere lesion in the cerebellum
slow, scanning speech; incoordination of limbs and staggering gait
what is neuroleptic malignant syndrome
Neuroleptic malignant syndrome (NMS) is a life-threatening neurologic emergency associated with the use of antipsychotic (neuroleptic) agents and characterized by a distinctive clinical syndrome of mental status change, rigidity, fever, and dysautonomia.
look up more about this as it may be
