Cerebellum - Presentation PDF

Presentation by Lois Stevens Cerebellum Senior Lecturer Brain Orientation Inputs/Outputs  Cerebellum Where does the cerebellum receive inputs from? Where does the cerebellum send outputs to?  Inputs Vestibular System Spinal Cord...

Presentation by Lois Stevens Cerebellum Senior Lecturer Brain Orientation Inputs/Outputs  Cerebellum Where does the cerebellum receive inputs from? Where does the cerebellum send outputs to?  Inputs Vestibular System Spinal Cord Cerebral Cortex (via pontine nuclei)  Functional Organisation Vestibulocerebellum Spinocerebellum Cerebrocerebellum  Vestibulocerebellum Named for its reciprocal links with the vestibular system – Receives information directly from vestibular receptors and vestibular nuclei as well as visual areas of the brain (INPUTS) – Sends information to vestibular nuclei in the brainstem (OUTPUTS)  Vestibulocerebellum Influences eye movements and postural muscles and thus regulates equilibrium  Spinocerebellum Somatosensory information from spinal cord (converges with sensorimotor information from cortex) (INPUTS) Information used to control ongoing movement via reticular formation and red nucleus in the brainstem (OUTPUTS)  Spinocerebellum Regulates gross limb movements  Task Draw a diagram showing the cortico - pontine cerebellar – thalamico-cortico pathway.  Cerebrocerebellum Receives information indirectly (via pons) from areas of cerebral cortex controlling distal limb movements (INPUTS) Sends information to cerebral cortex via motor thalamus (OUTPUTS)  Cerebrocerebellum Coordination of voluntary movements Planning of movements Ability to judge time intervals and produce accurate rhythms  Cerebellar Function Summary Posture and balance – regulates mm tone Voluntary Movements – especially fine movements Motor planning Motor learning Rhythm/Timing (Attention, speech, processing music) Cortex/Cerebellar Interaction Motor cortex the ability to execute movements. The cerebellum provides the tactics of the multiple muscle activation required to support and such define movements.  Function Cerebellum acts as a ‘comparator’ – receives information about the intended movement and also receives information about what actually happened – measures degree of error – makes correction as required  Function Feed-forward – Feedback Forms basis for motor learning Voluntary Automatic  Cortex/cerebellar Interaction While the CORTEX determines where to move the CEREBELLUM implements its proper timing and modulates the force given to every motor command TIMING, FORCE, DIRECTION AND SPEED Vision  Co-ordination What do we mean when we speak about co- ordination?  Coordination What are the components of coordinated movement? – Force – Direction – Timing – Velocity A disruption to these will result in decomposition of movement  Summary of Outputs Functional Sends Output Reaches Division to LMN via Vestibulo Vestibular Vestibulospinal Cerbellum Nuclei tracts Spino Reticular nuclei/ Reticulospinal/ cerebellum Red Nucleus Rubrospinal tracts Cerebro Motor and Corticospinal cerebellum premotor tracts cortices  Ataxia Lack of co-ordination – movement disorder common to all lesions of the cerebellum Refers to voluntary, normal strength movements, not associated with hypertonia, that are jerky and inaccurate  Cerebellar Disease Impairments of – Gait – Balance – Voluntary movements