Cerebellum External Configurations Cerebellum External Configurations - located in posterior cranial fossa - tentorium cerebelli (cerebrum), 4th ventricle (brain stem) - communicate with other structure via superior, middle, and inferior cerebellar peduncle superior, middle, and inferior cerebellar peduncle - longitudinal division Vermis, Paravermal Region, Cerebellar Hemisphere Vermis, Paravermal Region, Cerebellar Hemisphere - transverse division Anterior Lobe Anterior Lobe primary fissure primary fissure Posterior Lobe Posterior Lobe posterolateral fissure posterolateral fissure Flocculonodular Lobe Flocculonodular Lobe

F. The cerebellum- Has two lobed hemispheres that connect via the vermis. It has outer gray matter, imbedded white matter and deep gray matter (nuclei). Its surface ridges are called folia and they are separated by fissures. It coordinates movement and makes it smooth, it helps in maintaining posture and equilibrium and is involved in cognition.

Spinocerebellum Pontocerebellum Vestibulocerebellum

1. Purkinje cell 2. granule cell 3. basket cell 4. Golgi cell 5. stellate cell 6. climbing fiber 7. mossy fiber 8. parallel fiber 9. inferior olivary nucleus 10. deep cerebellar nuclei

Afferent Connections (1): Cerebellum Connections Cerebellum Connections

Vestibulocerebellar fiber linkage maintain the body’s balance and regulate ocular movement. vestibular nuclei inferior cerebellar peduncle flocculonodular lobe medical longitudinal fasciculus motor neuron of extraocular muscles vestibulospinal tract motor neuron of trunk muscle

Superior Cerebellar Peduncle Anterior Spinocerebellar Tract Anterior Spinocerebellar Tract Cerulocerebellar fiber Cerulocerebellar fiber Raphecerebellar fiber Raphecerebellar fiber Rubrocerebellar fiber Rubrocerebellar fiber Hypothalamocerebellar fiber Hypothalamocerebellar fiber

control muscular tension and regulate muscular movement Spinicerebellar fibra links and function direct cerebellar tract inferior cerebellar peduncle superior cerebellar peduncle vermis fastigial nucleus intermedial nucleus cortex of cerebellar hemisphere red nucleus of opposite side rubrospinal tract zona rolandica lateral corticospinal tract vestibular nucleus reticular formation of brain stem vestibulospinal tract reticulospinal tract

dominate the planning and coordination of refined movement of limbs The fibra links and function of cerebrocerebellum extensive area of cerebral cortex pontine nucleus lateral part cortex of cerebellar hemisphere dentate nucleus red nucleus ventrolateral nucleus of dorsal thalamus zona rolandica lateral corticospinal tract rubrospinal tract

Efferent Connections : 1. Superior Cerebellar Peduncle Cerebellothalamic fiber Cerebellothalamic fiber - from 3 deep nuclei to VPLo, VLc, CL - from 3 deep nuclei to VPLo, VLc, CL Cerebellorubral fiber Cerebellorubral fiber - from nucleus interpositus - from nucleus interpositus and dentate nucleus and dentate nucleus 2. Inferior Cerebellar Peduncle Fastigiovestibular fiber Fastigiovestibular fiber Cerebellum Connections Cerebellum Connections

Two types of fibers to cerebellar cortex 1. Climbing fibers a, project to dendritic trees of Purkinje neurons b. are extremely excitatory c. primarily originate from inferior olivary nucleus may be some contribution from pontine and reticular nuclei 2. Mossy fibers a. much more numerous than climbing fibers b. origination is spinocerebellar and pontocerebellar c. project to granule cell dendrites d. from granule cells, information is passed to dendritic branches of Purkinje cells. e. are extremely excitatory

Climbing and Mossy fibers are part of a circuit 1. excitatory input enters, is integrated throughout cells of cerebellar cortex, exits via axons of Purkinje cells 2. outflow is inhibitory 3. primary target of cerebellar outflow is deep cerebellar nuclei a. globose and emboliform axons project to red nucleus & reticular formation via superior cerebellar peduncles, then to cord via rubrospinal tract. b. dentate axons project to thalamus via superior cerebellar peduncles, and then to cerebral cortex c. fastigial axons project to vestibular nuclei and nuclei for cranial nerves III, IV, and VI via inferior cerebellar peduncles

Cerebellum Function Cerebellum Function  Maintenance of Equilibrium - balance, posture, eye movement - balance, posture, eye movement  Coordination of half-automatic movement of walking and posture maintenace walking and posture maintenace - posture, gait - posture, gait  Adjustment of Muscle Tone  Motor Leaning – Motor Skills  Cognitive Function

Balance

Motor Skill Pablo Casals

Posture Gait – Ataxia Tremor

CerebellarAtaxia Ataxic gait and position: Left cerebellar tumor Left cerebellar tumor a. Sways to the right in a. Sways to the right in standing position standing position b. Steady on the b. Steady on the right leg right leg c. Unsteady on the c. Unsteady on the left leg left leg d. ataxic gait d. ataxic gait abc d

Cerebellar tumors on vermis - Truncal Ataxia - Truncal Ataxia - Frequent Falling - Frequent Falling The child in this picture: - would not try to stand - would not try to stand unsupported unsupported - would not let go of the bed rail - would not let go of the bed rail if she was stood on the floor. if she was stood on the floor. CerebellarMedulloblastoma