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42 Cards in this Set
- Front
- Back
What are the four deep nuclei of the cerebellum? |
1. Dentate 2. Emboliform 3. Globose 4. Fastigial |
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The cerebellum is supplied by which arteries? |
1. Superior cerebellar artery supplies the superior hemispheres and vermis, the rostral aspect of the dentate nucleus, and the remaining deep nuclei 2. Posterior inferior cerebellar artery sipplies the lateral medulla and inferolateral surface of the cerebellum 3. Anterior inferior cerebellar artery supplies the inferior and ventral surface of the cerebellum as well as the ventral aspect of the dentate nucleus |
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What are the different layers of the cerebellum? |
1. Molecular (Purkinje cell dendrites, parallel fibers of the granule cells, basket cells, and stellate interneurons) 2. Purkinje 3. Granular (Golgi cells and granule cells) |
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Main output of the cerebellar cortex? |
Purkinje; all cell types in the cortex are GABAergic except the granule cells |
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Role of Granule cells? |
Only excitatory neuonrs; project to the molecular layer, where they become parallel fibers that synapse with Purkinje cell dendrites |
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Role of Golgi cells? |
Inhibit granule cells |
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Role of stellate and basket cells? |
Laterally inhibit Purkinje cells |
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Main inputs to the cerebellum? |
Mossy fibers and climbing fibers; both are excitatory and use L-glutamate |
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Role of mossy-parallel fiber input? |
Constant information regarding velocity and direction of movement |
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Where do mossy fibers originate? (4) |
1. Pontine nuclei (pontocerebellar pathway) 2. Spinal cord (spinocerebellar tract) 3. Vestibular nuclei (vestibulocerebellar tract) 4. Reticular formation |
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Climbing fibers originate where? |
Inferior olivary nucleus; provide input to deep nuclei and Purkinje cells |
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Role of climbing fibers? |
Regulate the response of Purkinje cells to mossy fiber input |
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Role of climbing fiber input? |
Help correct errors in movement |
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Functional subdivisions of the cerebellum? |
1. Vestibulocerebellum 2. Spinocerebellum 3. Cerebrocerebellum Based on the area of cerebellar cortex each involved in a particular pathway |
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Functional clusters of the cerebellum? |
Based on specific functions: 1. Motor 2. Oculomotor 3. Cognitive 4. Limbic |
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Vermis controls what? |
Spinal central pattern generator for gait via the reticulospinal system; also under contorl of the PPN and basal ganglia |
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Medial vermis receives input from where? |
Proprioceptive input from limbs via spinocerebellar tract and vestibular system |
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Lateral vermis projects where? |
Lateral vestibular nucleus, which gives rise to the lateral vestibulospinal tract (important for tone and posture, especially to extensor muscles) |
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Role of medial hemisphere or paravermal region? |
1. Sequence activation and coordination of agonist and antagonist muscles in multijoint movements; process proprioceptive information from the spinocerebellar neurons 2. Planning, timing, and initation of specific patterns of movement |
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Mechanism of paravermal cerebellum's role? |
Compares the actual and intended movement of limbs and then aids in correction; afferent input from motor cortex, ventral spinocerebellar tract, and dorsal spinocerebellar tract |
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Deep nuclei of the medial hemisphere? |
Globose and emboliform |
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Role of dentate nucleus? |
Discharge and provide a trigger signal to the motor cortex and initiate a movement with a sensory stimulus |
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The dorsal vermis controls what? |
Amplitude, direction, and velocity of saccadic eye movements |
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Vestibulocerebellum consists of ? |
1. Flocculus 2. Paraflocculus 3. Nodulus |
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Input to the vestibulocerebellum comes from? |
Mossy fibers from the vestibular nuclei, smooth pursuit pathway (middle superior temporal area via the dorsolateral pontine nuclei), and the nucleus preposituys hypoglossi and medial vestibular nuclei (involved in gaze holding) |
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Efferent axons from thje flocculus and paraflocculus project where? |
Medial vestibular nuclei and then to the cranial nerve nuclei involved in ocular movement |
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Dorsal vermis receives input from where? |
Paramedian pontine reticular formation (excittatory burst neuron for horizontal saccades) and the nucleus reticularis tegmentum pontis (relay from the frontal eye fields and superior colliculus for planning saccades) |
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Fastigial nuclei project where? |
Contralateral brainstem premotor burst and omnipause neurons controlling saccades |
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Purkinje cells of the dorsal vermis discharge ____ and project to the ___ |
before the contralateral saccades; fastigical nuclei |
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Limbic circuitry of the cerebellum (5) |
The lateral aspect of the posterior lobe of the cerebellum appears to be important in language, verbal working memory, spatial tasks, executive function, and emotional processing |
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Role of inferior olive? |
Compare intended motor commands to actual motor commands from the cerebral cortex, the brainstem nuclei, and the feedback afferent system; if inputs do not match, an increase in firing of the inferior olivary recults in an error signal that modifies Purkinje response to mossy fibers |
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Projections from the inferior olive? |
Low-frequency, synchronized oscillatory activity via the climbing fiber system to the cerebellar nuclei and the Purkinje cells |
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How is the inferior olive regulated? |
BNy cerebellar nuclei via 2 competing connections: they project an inhibitory GABAergic projection to the inferior olive, in addition, they project an indirect excitatory projection via the red nucleus |
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Saccadic dysmetria may suggest a lesion where? |
1. Flocculus or paraflocculus 2. Dorsal vermis |
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Gaze-evoked nystagmusmay suggest a lesion where? |
Flocculus or paraflocculus |
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Opsoclonusmay suggest a lesion where? |
Dorsal vermis |
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Gait ataxiamay suggest a lesion where? |
Vermis |
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Limb ataxiamay suggest a lesion where? |
Cerebellar hemisphere |
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Tremormay suggest a lesion where? |
Cerebellar-thalamocortical loop |
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Essential tremormay suggest a lesion where? |
Guillain-Mollaret triangle (dentate-red nucleus-inferior olive pathway) |
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Palatal myoclonusmay suggest a lesion where? |
Guillain-Mollaret triangle (dentate-red nucleus-inferior olive pathway) |
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What is the ataxic hemiparesis syndrome? |
Common manifestation of ischemic stroke, often due to a lacunar mechanism. Mild upper motor neuron weakness but moderate to severe ataxia on the weak side. Impairment of both the cerebrocerebellar circuit and the corticospinal tract. |