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Explore the intricate functions and impact of lesions in the cerebellum, a key neural structure with vital roles in sensory integration, motor coordination, and balance. Discover how different divisions of the cerebellum contribute to distinct clinical deficits and the effects of damage. Learn about the vestibulocerebellum, spinocerebellum, and neocerebellum, and how they influence reflexes, movement control, and voluntary actions. Understand the implications of alcohol on cerebellar functioning and its significance in sobriety tests.
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Cerebellum • More cells in cerebellum than rest of nervous system combined • Receives sensory info from somatosensory, vestibular, visual and auditory areas
3 divisions of cerebellum • Vestibulocerebellum • Spinocerebellum • Neocerebellum • Different lesions produce different clinical deficits
Vestibulocerebellum • Input from & output to brainstem vestibular nuclei • For balance • For coordinating eye & body movements • Vestibulo-ocular reflex • Allows eyes to remain fixed on an object despite head or body movements
Vestibulocerebellum • Cerebellar nystagmus • Inability to fixate on object. • eyes drift away from it, with rapid return.
Vestibulocerebellum • Damage decreased reflexes • Postural instability • Experience nausea
Spinocerebellum • Ascending sensory inputs via S.C. • Descending motor outputs • Damage problems with smooth control of motor movements • Problems walking • Bowlegged stance
Spinocerebellum • Damage rapid pointing often extends past target • Hypermetria • Damage difficulty stopping movement • As arm approaches target, goes into oscillations
Neocerebellum • Control of voluntary movements
Neocerebellum • Damage leads to: • Clumsy movements • Hypermetria • Especially in sequences of gestures • Movements req. coordination of many body parts • Prolonged initiation of movements
Neocerebellum • Lesions result in deficits similar to spinocerebellum • Neocerebellum - planning movements • Spinocerebellum – regulating actual performance
Cerebellum • Alcohol may affect cerebellum • Sobriety tests often assess cerebellar functioning • Balance • Touching finger to nose