OTH 509: Cerebellum 2023 with complete solution

the cerebellum is which type of system? extrapyramidal motor system what does it mean to be an extrapyramidal motor system? - has no direct descending input to the LMN - but communicates with the LMN using all the descending pathways what are the three lobes of the cerebellum? - flocculonodular lobe - anterior lobe - posterior lobe what does the floculonodular lobe of the cerebellum do? - knowns as the vestibulocerebellum - also called the "archi' cerebellum - function: balance what does the anterior lobe of the cerebellum do? - also called the "paleo" cerebellum - regulation of tone what does the posterior lobe of the cerebellum do? - also called "Neo" cerebellum - COORDINATION which lobe of the brain is the biggest? posterior lobe what fissure separates the anterior and posterior lobe? primary fissure what fissure separates the posterior and flocculonodular lobe? posterolateral fissure what is the midline of the cerebellum called? vermis what are the four cerebellar nuclei? - dentate - emboliform - globose - fastigial The dentate nucleus is important for ______. balance what do the cerebellar peduncles do? connect cerebellum to brain stem the superior cerebellar peduncles connects the cerebellum to the _______. midbrain the middle cerebellar peduncles connects the cerebellum to the _______. pons the inferior cerebellar peduncles connects the cerebellum to the _______. medulla the inferior cerebellar peduncle is made up of the _______ and ________. - resiform body - juxtaresiform body which cerebellar peduncles carry info TO the cerebellum? - superior cerebellar peduncle - middle cerebellar peduncle where does the info of the restiform body come from? input from the spinal cord and olivary nucleus where does the info of the juxtarestiform body come from? gives priority to the vestibular system where does the info of the middle cerebellar peduncle come from? only carries info from the pons where does the dorsal spinocerebellar pathway begin? - proprioceptive afferent, muscle spindle, joint receptor, etc. from LE where does the dorsal spinocerebellar pathway go after the proprioceptor? - entered the cord from C8-L2-3, synapses in a nucleus called nucleus dorsalis (aka clarks column) where does the dorsal spinocerebellar pathway enter the cerebellum? - via the inferior peduncle what does the dorsal spinocerebellar pathway do? proprioception of the LE and trunk where are the first order neurons from the cuneocerebellar pathway? - proprioceptor afferents from the UE - enters cord C8 and ascends without synapsing where does the 1st order neuron of the cuneocerebellar pathway synapse? - a nucleus in the medulla called lateral or accessory cuneate nucleus - then enters the cerebellum is the cuneocerebellar pathway ipsilateral, bilateral, or contralateral? ipsilateral where does the ventral or anterior spinocerebellar pathway begin? - primary proprioceptive afferents where does neuron 2 of the ventral or anterior spinocerebellar pathway go? - crosses and ascends up to the cerebellum where does the ventral or anterior spinocerebellar pathway enter the cerebellum? through the superior cerebellar peduncle is the ventral or anterior spinocerebellar pathway ipsilateral, bilateral, or contralateral? - ipsilateral - even though it crosses at neuron 2, after it enters the cerebellum it crosses again which makes it ipsilateral if you have a unilateral lesion to the cerebellum, the result is _______. ipsilateral what do projections of the cerebellum via the superior cerebellar peduncle do? - project FROM the cerebellum where do the projections from the cerebellum (via the superior cerebellar peduncle) cross? in the midbrain tegmentum where do the projections from the cerebellum (via the superior cerebellar peduncle) go after crossing (4 different places)? - reticular formation - red nucleus - olivary nucleus - cortex via VL/VA of the thalamus **no direct descending pathway to the LMN how is the cerebellum related to motor learning? - because it receives BOTH proprioceptive feedback about ACTUAL sensory consequences from the spinal cord and EXPECTED sensory consequences from the brain via the pons, the cerebellum can compare these and refine the motor program resulting in motor learning what are the three layers of the cerebellar cortex? - granule (deepest) - purkinje (middle) - molecular (superficial) The mossy fiber ending on the granule cell is called a ______. the entire apparatus is called _____. - rosette - glomerulus what do the granule cells do? - characterized by projecting to the molecular layer and running likes wires across multiple purkinje cells deep nuclei are _____ in outflow. facilitatory ALL Purkinje cells ______ deep nuclei. inhibit explain how the calibrates for moment and responds quickly: •Deep Nuclei are facilitatory in outflow •ALL Purkinje cells INHIBIT deep nuclei •ALL Interneurons are INHIBITORY •DISINHIBITION RESULTS IN RELEASE •NET RESULT ALLOWS CEREBELLUM TO CALIBRATE FOR MOVEMENT AND RESPOND QUICKLY [ON-OFF] another explanation: •Mossy and climbing fibers enter the cerebellum and synapse with the deep nuclei, driving facilitation •Then go on to: •Synapse directly on the Purkinje, which then inhibits the deep nuclei •Synapse on the Granules cells, which go to molecular layer, bifurcate and facilitate Purkinje, which then inhibit deep nuclei •And the interneurons can modulate the system the cortex is also involved in ____ and ____ functions. - cognitive - emotions true or false: cerebellum isn't plastic. FALSE THE CEREBELLUM IS EXTREMELY "PLASTIC" - Why we can learn new movements throughout the life what are the signs of a classic cerebellar lesion? •Hypotonia •Nystagmus •Dysmetria •Dysdiadochokinesia •Ataxia •Tremor (intention tremor) •Rebound phenomenon •Speech may be scanning why is there nystagmus seen in a cerebellar lesion? because the vestibular system is the best friend of the cerebellum what is Dysmetria? Dysmetria is the inability to estimate the ROM necessary to meet the target. Evident when the individual tries to touch the nose. what is Dysdiadochokinesia? inability to perform rapid alternating movements what is ataxia? the loss of full control of bodily movements what is the difference between tremors in cerebellar and basal ganglia lesions? - Tremor in cerebellum gets worse when we begin to move but in the basal ganglia it gets better with movement (resting) types of cerebellar problems: •TBI (coup-contre-coup) •Primary damage: trauma as in gunshot •Tumor •Stroke •Disease (multiple sclerosis/degenerative) •Alcoholism