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 - longitudinal division Vermis, Paravermal Region, Cerebellar Hemisphere - transverse division Anterior Lobe ------------ primary fissure Posterior Lobe ------------ posterolateral fissure Flocculonodular Lobe

Subdivision of Flocculonodular Lobe Nodulus Flocculus Subdivision of Anterior Lobe Vermis Hemisphere Lingula Central Lobule Ala Central Lobule postcentral fissure Culmen Quadriangular Lobule Cerebellum External Configurations

Subdivision of Posterior Lobe Vermis Hemisphere Declive Simple Lobule postcentral fissure Folium Superior Semilunar Lobule horizontal fissure Inferior Semilunar Lobule Tuber Gracile Lobule prepyramidal fissure Pyramis Biventer Lobule secondary fissure Uvula Tonsil Cerebellum External Configurations

Cerebellar Cortex Molecular Layer Purkinje Cell Layer Granular Layer Corpus Medullare (Medullary Center) Deep Cerebellar Nuclei Fastigial Nuclei Nucleus Interpositus Emboliform Nucleus Globose Nucleus Dentate Nucleus Cerebellum Internal Configurations

1. fastigial nucleus 2. globose nucleus 3. emboliform nucleus 4. dentate nucleus Deep Nuclei

Cerebellar Cortex I. Molecular Layer Stellate Cell --- taurine (inhibitory) afferent: parallel fiber efferent: Purkinje cell dendrite Basket Cell ---- GABA (inhibitory) afferent: parallel fiber efferent: Purkinje cell soma Parallel Fiber granule cell axon Purkinje Cell Dendrite Cerebellum Internal Configurations

Cerebellar Cortex II. Purkinje Cell Layer Purkinje Cell -- 15,000,000 in number -- GABA (inhibitory) afferent: parallel fiber climbing fiber stellate cell basket cell efferent: deep cortical nuclei Bergmans glial cell Cerebellum Internal Configurations

Cerebellar Cortex III. Granular Layer Granular Cell -- 50,000,000,000 in number -- glutamic acid (excitatory) afferent: mossy fiber efferent: Purkinje cell dendrite basket cell, stellate cell Golgi cell Golgi Cell -- GABA (inhibitory) afferent: parallel fiber, mossy fiber rosette efferent: granule cell dendrite Cerebellum Internal Configurations

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

Synaptic Glomerulus Afferent terminals on granular layer Mossy Fiber Rosette -- afferent fibers except inferior olivary input -- 2/3 of medullary center Granular Cell Dendrite -- main afferent input Golgi Cell Axon -- synapse on granule cell dendrite -- GABA (inhibitory) - Surrounded by Astrocyte Foot Process Cerebellum Internal Configurations

Synaptic Glomerulus

Classification by Phylogenetic and Ontogenic Development Archicerebellum Paleocerebllum Neocerebellum Classification by Afferent Connection Vestibulocerebellum Spinocerebellum Pontocerebellum Classification by Efferent Connection Vermis Paravermal Region Cerebellar Hemisphere Cerebellum Classifications

Archicerebellum (nodulus) Archicerebellum (flocculus) Paleocerebellum Neocerebellum

Spinocerebellum Pontocerebellum Vestibulocerebellum

Afferent Connections (1): 1. Inferior Cerebellar Peduncle Restiform Body Posterior Spinocerebellar Tract Olivocerebellar tract Cuneocerebellar Tract Reticulocerebellar Tract Juxtarestiform Body Vestibulocerebellar Tract Primary Vestyibular Fiber Cerebellum Connections

Afferent Connections (2): 2. Middle Cerebellar Peduncle Pontocerebellar fiber Corticopontocerebellar Fiber Reticulocerebellar Fiber 3. Superior Cerebellar Peduncle Anterior Spinocerebellar Tract Cerulocerebellar fiber Raphecerebellar fiber Rubrocerebellar fiber Hypothalamocerebellar fiber Cerebellum Connections

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

MLF Main Connections of the Vestibulocerebellum lower motor neuron LMN vestibulospinal tract FASTIGIAL NUCLEUS Vestibular Organ Floculonodular Lobe Vermis ARCHICEREBELLUM VESTIBULAR NUCLEUS

Main Connections of the Paleocerebellum lower motor neuron SPINAL CORD rubrospinal tract NUCLEUS INTERPOSITUS Inferior Olivry Nucleus ANTERIOR LOBE PARAVERMAL ZONE PALEOCEREBELLUM RED NUCLEUS spinocerebellar tract

CEREBRAL CORTEX DENTATE NUCLEUS Main Connections of the Neocerebellum lower motor neuron LMN pyramidal tract POSTERIOR LOBE CEREBELLAR HEMISPHERE THALAMUS NEOCEREBELLUM Pontine Nucleus

upper motor neuron UMN BASAL GANGLIA Pyramidal Tract and Associated Circuits lower motor neuron UMN pyramidal tract Cerebellum

Reticular Formation CEREBELLUM Cerebellum and Automatic Motor Control Lower Motor Neuron (LMN) Motor Cortex Red Nucleus Vestibular Nucleus Proprioceptors

Corticonuclear Connections A zone ---------- fastigial nucleus medial vestibular nucleus B zone ---------- lateral vestibular nucleus C 1 , C 3 zone --- emboliform nucleus C 2 ---------------- globose nucleus D 1 ---------------- parvocellular portion of dentate nucleus D 2 ---------------- magnocellular portion of dentate nucleus Cerebellum Connections

1. vermis 2. paravermal region 3. cerebella hemisphere 4. nodulus 5. flocculus 6. fastigial nucleus 7. globose nucleus 8. emboliform nucleus 9. dentate nucleus 10. medial vestibular nucleus 11. lateral vestibular nucleus

Olivocerebellar Connections Caudal portion of medial and dorsal accessory olivary nucleus ----------------- vermis of cerebellar cortex (A and B) fastigial nucleus vestibular nucleus Rostral portion of medial and dorsal accessory olivary nucleus ----------------- paravermal region (C 1 , C 2 , C 3 ) nucleus interpositus Principal Inferior Olivary Nucleus ----------------- cerebellar hemisphere (D 1 , D 2 ) dentate nucleus Cerebellum Connections

medial and dorsal accessory olivary nucleus caudal portion rostral portion Principal Inferior Olivary Nucleus

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

Balance

Motor Skill Pablo Casals

Cerebellum Clinical Syndromes Ataxia : incoordination of movement - decomposition of movement - dysmetria, past-pointing - dysdiadochokinesia - rebound phenomenon of Holmes - gait ataxia, truncal ataxia, titubation Intention Tremor Hypotonia, Nystagmus Archicerebellar Lesion : medulloblastoma Paleocerebellar Lesion : gait disturbance Neocerebellar Lesion : hypotonia, ataxia, tremor

Posture Gait Ataxia Tremor

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

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