Cerebellum External Configurations located in posterior cranial fossa

Cerebellum External Configurations - located in posterior cranial fossa - tentorium cerebelli (cerebrum), 4 th 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

Cerebellum External Configurations Subdivision of Flocculonodular Lobe Nodulus Flocculus Subdivision of Anterior Lobe Vermis Lingula Central Lobule Hemisphere 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 Internal 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

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

Cerebellum Internal Configurations 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 in number -- GABA (inhibitory) afferent: parallel fiber climbing fiber stellate cell basket cell efferent: deep cortical nuclei Bergman’s glial cell

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

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

Cerebellum Internal Configurations 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

Synaptic Glomerulus

Cerebellum Classifications 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

Archicerebellum (nodulus) Archicerebellum (flocculus) Paleocerebellum Neocerebellum

Spinocerebellum Pontocerebellum Vestibulocerebellum

Cerebellum Connections 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

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

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

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

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

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

Cerebellum Connections 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

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

Cerebellum Connections 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

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

a d b c 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

Cerebellar Medulloblastoma 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.