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Exam 4 - Section 4
Cerebellum
57
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Undergraduate 3
11/19/2015

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Term
The cerebellum is a ______; it compares the intended movement with the actual performance & corrects errors in subsequent movements through motor learning
Definition
comparator
Term
Cerebellar lesions do not cause paralysis, but uncoordinated movements of the limbs, trunk, & eyes (_____), impaired balance, loss of muscle tone, & inability to update motor programs
Definition
ataxia
Term
The outer gray matter of the cerebellum, the ______, is deeply folded to form rounded transverse folia & is divided into anterior, posterior, & flocculonodular lobes
Definition
cerebellar cortex
Term
In the mediolateral dimension, the cerebellum is divided into a central ______ & ______/______ hemispheres
Definition
vermis; intermediate & lateral
Term
Inputs & outputs to the cerebellum travel through the superior, middle, & inferior _______
Definition
cerebellar peduncles
Term
Buried in the white matter of the cerebellum is additional gray matter, the ______
Definition
deep cerebellar nuclei
Term
The ______ cerebellar nucleus is the lateral most & largest
Definition
dentate
Term
The ______ cerebellar nuclei are paired
Definition
interposed
Term
The ______ cerebellar nucleus is the medial most
Definition
fastigial
Term
All afferents to the cerebellar cortex also give off collaterals to the ______
Definition
deep cerebellar nuclei
Term
Each cerebellar hemisphere coordinates movements on the ______ side
Definition
ipsilateral
Term
Each deep cerebellar nucleus is connected to a different region of the cerebellar cortex, forming parallel functioning systems: ______, ______, & ______
Definition
vestibulocerebellum, spinocerebellum, cerebrocerebellum
Term
The _____ receives sensory information mainly from sensorimotor cortices & projects back to premotor areas, forming a parallel system to the basal ganglia for motor planning & programming
Definition
cerebrocerebellum
Term
Through the corticopontine circuit, the ______ receives motor input regarding the intended movement, i.e. efference copy
Definition
spinocerebellum
Term
The spinocerebellum receives peripheral sensory information regarding the evolving movement & then mediates ______
Definition
error correction
Term
The vestibulocerebellum in the _____ lobe receives mainly vestibular input
Definition
flocculonodular
Term
The vestibulocerebellum is the only cerebellar division to receive direct ______ from primary sensory afferents
Definition
inputs
Term
The output of the vestibulocerebellum is directed to the ______, which relay information to the spinal cord for control of proximal muscles used in balance & to ______ for reflexive eye movements
Definition
vestibular nuclei; oculomotor nuclei
Term
Damage to the flocculonodular lobe causes ______ & disturbances of equilibrium (______) with a wide-based standing position
Definition
nystagmus; truncal ataxia
Term
The ______ consists of both the vermis & intermediate hemispheres
Definition
spinocerebellum
Term
The ______ receives vestibular, auditory, somatosensory, & visual information
Definition
vermis
Term
The vermis transmits to the ______ nucleus which regulates medial descending pathways
Definition
fastigial
Term
The ______ of the spinocerebellum receives somatosensory input via spinocerebellar & trigeminal pathways
Definition
vermis
Term
The output of the vermis via the _____ nucleus is relayed primarily to the descending vestibulospinal & reticulospinal pathways to adjust movements of the proximal musculature
Definition
fastigial
Term
Inputs to the _____ spinocerebellar system include proprioceptive information from distal body parts & cortical input via pontocerebellar fibers
Definition
intermediate
Term
The intermediate division relays output via the _____ nuclei to the rubrospinal pathway & then through the VL thalamus to the corticospinal tract
Definition
interposed
Term
The intermediate system adjusts movements of the ______ musculature
Definition
distal
Term
The spinocerebellum is ______ organized, so that deficits caused by lesions depend on their precise location
Definition
soamtotopically
Term
Lesions of the ______ of the vermis produce unsteadiness of walking (gait ataxia), suggesting that cerebellar outputs normally modify the central pattern generators for walking
Definition
anterior lobe
Term
Patients with vermis damage may also show facial disorders like ______ (slurred, slow speech)
Definition
dysarthria
Term
Chronic alcohol abuse can lead to cerebellar damage & permanent nystagmust, ataxia, & other neurological problems (______)
Definition
Wernicke's encephalopathy
Term
Damage to the intermediate zone leads to limb ataxia & ______ (errors in the smoothness & direction of targeting movements)
Definition
dysmetria
Term
The inability to target an object at the end of a reach, with constant over & undershooting, creates the condition known as ______
Definition
intention tremor
Term
Lesions of the interposed or fastigial nuclei lead to _____, apparently from lack of excitatory drive to descending pathways that activate A gamma motor neurons
Definition
hypotonia
Term
The cerebrocerebellum is innervated exclusively by the _____ nucleus
Definition
pontine
Term
The output of the cerebrocerebellum is directed toward the _____ nucleus, which relays back to the premotor cortex via the VL thalamus
Definition
dentate
Term
The cerebrocerebellum assists the premotor regions in _______
Definition
selecting the most efficient motor program
Term
Lesions of the cerebrocerebellum cause ______ of movements
Definition
delayed termination & initiation
Term
_______ is the term for errors in smoothness & direction of targeting movements
Definition
dysmetria
Term
______ is the inability to perform a series of rapid alternating movements
Definition
dysdiadochokinesia
Term
ION inputs constitute the _____ & have powerful effects on cerebellar activity & mediate motor learning
Definition
climbing fibers
Term
The ______ layer has many connections but sparse neurons: basket cells & stellate cells
Definition
molecular
Term
The ______ layer contains a single row of large, isoplanar Purkinje neurons that form the sole output of the cerebellar cortex
Definition
Purkinje
Term
The _____ layer has densely packed granule cells & occasional Golgi cells
Definition
granular
Term
One ______ contacts up to 10 Purkinje cells through proximal synapses
Definition
climbing fiber
Term
Powerful excitatory contacts from climbing fibers drive bursts of action potentials called ______ in Purkinje cells
Definition
complex spikes
Term
______ are direct cerebellar afferents from multiple sources but they innervate Purkinje cells indirectly
Definition
mossy fibers
Term
Mossy fibers excite 50-60 ______ dendrites, whose axons ascend to the molecular layer & branch at right angles to form parallel fibers
Definition
granule cells
Term
Activation of ______ leads to feedback inhibition of the granule cells
Definition
Golgi cells
Term
Golgi cells also get some mossy fiber input & therefore create ______
Definition
feedforward inhibition
Term
Parallel fibers synapse onto _____, whose distal connections to Purkinje cells mediate only weak inhibition
Definition
stellate cells
Term
Basket cells mediate ______ inhibition on the Purkinje cell
Definition
strong
Term
The axons of basket cells branch perpendicular to the long axis of the folia, so that they inhibit Purkinje cells lateral to those that are excited by the parallel fibers (i.e. ______)
Definition
lateral inhibition
Term
______ is the ability to update motor programs with practice to improve effectiveness & efficiency
Definition
motor learning
Term
Climbing fiber influence on mossy fiber influence on Purkinje cell activity forms the basis for ______
Definition
motor learning
Term
The complex spikes appear to adjust the Purkinje cell response to the parallel fiber via a form of plasticity called _____
Definition
long term depression
Term
A ______ interaction is when one synapse modifies the strength of another synapse
Definition
heterosynaptic
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