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49 Cards in this Set
- Front
- Back
How does the cerebellum exert its effects on motor behavior?
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It affects the upper motor neurons
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How does the cerebellum act as a comparator?
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It compares the intended movement (info from cortex) to the actual movement (info from the sensory pathways)
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What separates the anterior and posterior lobes of the cerebellum?
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The primary fissure
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What separates the posterior lobe from the flocculonodular lobe?
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The posterolateral fissure
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What is the major source of output from the cerebellum?
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The deep nuclei
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What are the four deep nuclei?
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Fastigial, globose, emboliform, and dentate
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What are the five cells types of the cerebellar cortex?
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Purkinje, basket, golgi, stellate, and granule
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Which cells of the cerebellum are inhibitory and which are excitatory?
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All are inhibitory except for the granule cells, which are excitatory
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What are the three layers of the cerebellum?
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molecular, purkinje cell layer, and granule cell layer
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What are the two fibers called that input to the cerebellum ?
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Climbing fibers and mossy fibers
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What path do the climbing fibers take ?
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They originate in the inferior olivary complex, decussate and enter the cerebellum via the inferior cerebellar peduncle
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From where do the mossy fibers come?
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They arise from various locations: all 4 spinocerebellar tracts, vestibular nerve and nuclei, and pontine nuclei
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What does the main excitatory loop constitute?
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Input fibers and deep cerebellar nuclei, which project out of the cerebellum to descending motor systems; all of these cells are excitatory
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What cells do the climbing fibers contact directly?
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purkinje cells
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What do the mossy fibers contact?
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Mossy fibers contact granule cells in glomeruli
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What do the granule cells contact?
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Granule cells contact purkinje cells
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What forms the main output of the cerebellar cortex and what sort of stimulation is it?
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The main output of the cerebellar cortrex comes from the purkinje cells; they are inhibitory to deep cerebellar nuclei and vestibular nuclei
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What types of cells are golgi, basket, and stellate cells and what is their function?
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They are inhibitory interneurons that alter granule cell or purkinje cell activity
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What are the three functional subdivisions of the cerebellum?
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The vestibulocerebellum, spinocerebellum, and cerebrocerebellum
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What are the components of the vestibulocerebellum and what is it's function?
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Flocculonodular lobe and fastigial nucleus; they play a role in balance and eye movements
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What are the components of the spinocerebellum and what role do they play?
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Vermis and paravermal parts of the hemishperes, interposed nuclei (globose and emboliform); they play a role in motor execution (regulation of tone, posture, and locomotion)
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What are the components of the cerebrocerebellum and what role do they play?
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Lateral hemispheres and dentate nucleus; they play a role in motor planning and coordination
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What are the inputs of the vestibulocerebellum? (3)
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(1) vestibular nerve fibers (2) vestibular nuclei (3) inferior olive
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The outputs of the vestibulocerebellum come from what parts and go to which tracts (3)?
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Output comes from the fastigial nucleus (and purkinje cells to vestibular nuclei) and send info to (1) vestibular nuclei (2) reticular formation (3) VL of thalamus
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What does the spinocerebellum do?
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It plays a role in execution of movement, compensates for loads, regulates muscle tone, maintains posture, and guides limb movements
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What are the inputs to the spinocerebellum (2)?
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(1) Sensory tracts from the spinal cord and trigeminal system (2)the inferior olive
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What are the two places of output from the spinocerebellum and where does each send output?
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Vermis: (1)reticular formation (2) vestibular nuclei; paravermal: (1) red nucleus (2)VL of thalamus (3) inferior olive
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What is the function of the cerebrocerebellum?
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coordination and planning of voluntary movements
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What are the inputs to the cerebrocerebellum?
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pontine nuclei and the inferior olive
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What is the nuclei of the cerebrocerebellar lobe?
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dentate
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What are the outputs of the cerebrocerebellar lobe
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(1) red nucleus (2) VL of thalamus
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Besides the rubrospinal tract, what pathway originates at the red nucleus?
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The rubro-olivary tract projects to the inferior olive (which in turn projects to the cerebellum)
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What are the two components of the inferior cerebellar peduncle?
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(1) restiform body (2) juxtarestiform body- contains vestibular inputs and outputs
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What are the inputs that travel through the superior cerebellar peduncle?
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ventral spinocerebellar
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What are the major inputs that travel through the middle cerebellar peduncle?
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pontine nuclei
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What are the major inputs that travel through the inferior peduncle?
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inferior olive, vestibular nerves and nuclei, dorsal spinocerebellar tract, cuneocerebellar tract, rostral spinocerebellars
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All of the cerebellar outputs travel through which peduncle with the exception of what?
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The superior with the exception of vestibular nuclei
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Cerebellar damage causes ipsilateral or contralateral defects?
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ipsilateral
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What are 3 major signs of cerebellar disease?
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(1)hypotonia (2)intention tremor (3) ataxia
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What is intention tremor? It is caused why damage to which part of the cerebellum?
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A tremor that occurs only during movement and stops at rest; it is caused by damage to the spinocerebellum
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What is ataxia?
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lack of coordination of voluntary movements; includes dysmetria
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What is dysmetria
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Errors in range and motion, "mismeasurement"
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What is dysarthria?
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Disorder in speech, can be cerebellar or non-cerebellar
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What is dysdiadochokinesia
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Inability to sustain rhythmical alternating movements; distinct cerebellar sign
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What is decomposition of movement? Damage to what part of the cerebellum leads to this?
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The movement of one joint at a time; common with lateral hemisphere lesions; caused by damage to the cerebrocerebellum
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What is lack of check?
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The inability to stop a limb as resistance is suddenly removed
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Lesions of the vermis or fastigial nucleus may be associated with what symptoms?
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Problems with the trunk, whole body may sway, dysarthria
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What sort of symptoms would be associated with lesions of the paravermal or interposed nuclei?
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Ataxia of limbs, intention tremor
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What sort of symptoms would be seen with a lesion to the lateral hemisphere or dentate nucleus?
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delayed initiation of movements, disruption of motor planning; decomposition of movements
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