Clinical Case A patient delays initiation of movement, displays an uneven trajectory in moving her hand from above her head to touch her nose, and is uneven in her attempts to demonstrate rapid alternation of pronating and supernating movements of the hand and forearm. Which regions of the brain is most likely contains the lesion?

Clinical Case A 55-year-old male had been complaining about his having difficulty in coordinating the use of his arms in meaningful ways. For example, when examined by a neurologist, the patient was unable to move his finger accurately to his nose from his side when requested to do so but instead he would undershoot or overshoot the target. He also had difficulty in making Rapid alternating rotational movements of the hand. The neurologist believed that the patient was suffering from a disorder that resulted in a lesion of a region of the cerebellum or structures related to it. Which regions of the cerebellum is most likely contained this lesion

Cerebellum External features 1.located in posterior cranial fossa. 2.Communicate with brain stem by cerebellar peduncles. Superior cerebellar peduncles( Brachium conjunctiva) Middle cerebellar peduncles (Brachium pontis) Inferior cerebellar peduncle (Restiform Body

Crebellum External features cont..

Cerebellum Classification Classification Archicerebellum (Equilibrium, Tone & Posture of trunk Muscles) Paleocerebllum (Tone & Posture of limb Muscles) Neocerebellum (Smooth performance of skilled act by coordination of move) Classification by its Connections Vestibulocerebellum Spinocerebellum cerebrocerebellum

Crebellum External features cont.. Subdivision of Flocculonodular Lobe Nodulus Flocculus Subdivision of Anterior Lobe Vermis Hemisphere Lingula Central Lobule Ala Central Lobule postcentral fissure Culmen Quadrangular Lobule

Crebellum External features cont.. Subdivision of Posterior Lobe Vermis crebellar Hemisphere Declive Simple Lobule postcentral fissure Folium Superior Semilunar Lobule horizontal fissure Inferior Semilunar Lobule Tuber Gracile Lobule prepyramidal fissure Pyramid Biventer Lobule secondary fissure Uvula Tonsil

Crebellum Internal features cont.. Cerebellar Cortex Molecular Layer Purkinje Cell Layer Granular Layer Deep Cerebellar Nuclei Fastigial Nuclei (Nucleus Interpositus) Emboliform Nucleus Globose Nucleus Dentate Nucleus

Crebellum Internal features cont.. Cerebellar Cortex I. Molecular Layer Stellate Cell (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 features cont.. II. Purkinje Cell Layer Purkinje Cell -- 15,000,000 in number -- GABA (inhibitory) afferent: parallel fiber climbing fiber stellate cell basket cell efferent: deep cerebellar nuclei nuclei

Cerebellum Internal features cont.. 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 features cont.. 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 Connections 1. Inferior Cerebellar Peduncle Restiform Body Restiform Body Posterior Spinocerebellar Tract Posterior Spinocerebellar Tract Olivocerebellar tract Olivocerebellar tract Cuneocerebellar Tract Cuneocerebellar Tract Reticulocerebellar Tract Reticulocerebellar Tract Juxtarestiform Body Juxtarestiform Body Vestibulocerebellar Tract Vestibulocerebellar Tract Primary Vestyibular Fiber Primary Vestyibular Fiber

Cerebellum Connections Afferent Connections (2): 2. Middle Cerebellar Peduncle Pontocerebellar fiber Pontocerebellar fiber Corticopontocerebellar Fiber Corticopontocerebellar Fiber Reticulocerebellar Fiber Reticulocerebellar Fiber 3. 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

Cerebellum Connections Efferent Connections: 1. Superior Cerebellar Peduncle Cerebellothalamic fiber - From 3 deep nuclei to VPLo, VLc, CL Cerebellorubral fiber - From nucleus globusus And dentate nucleus 2. Inferior Cerebellar Peduncle Fastigiovestibular fiber Descending portion of Uncinate fasciculus

Cerebellar Pathway

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

Main Connections of the Paleocerebellum lower motor neuron lower motor neuron SPINAL CORD rubrospinal tract tract NUCLEUS NUCLEUSINTERPOSITUS Inferior Inferior Olivry OlivryNucleus ANTERIOR ANTERIOR LOBE LOBEPARAVERMAL ZONE ZONE PALEOCEREBELLUM RED NUCLEUS RED NUCLEUS spinocerebellar tract

CEREBRAL CORTEX CORTEXCEREBRAL DENTATENUCLEUSDENTATENUCLEUS Main Connections of the Neocerebellum lower motor neuron lower motor neuron LMN LMN pyramidal tract tract POSTERIORLOBECEREBELLAR HEMISPHERE HEMISPHEREPOSTERIORLOBECEREBELLAR THALAMUSTHALAMUS NEOCEREBELLUM PontineNucleusPontineNucleus

upper motor neuron UMN UMN BASALGANGLIABASALGANGLIA Pyramidal Tract and Associated Circuits lower motor neuron UMN UMN pyramidal tract CerebellumCerebellum

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

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

Cerebellum Disorders Ataxia: incoordination of movement - decomposition of movement - dysmetria, past-pointing - dysdiadochokinesia(Adidydakokinesia) - rebound phenomenon of Holmes - gait ataxia, truncal ataxia, titubation Intention Tremor Hypotonia, Nystagmus

Cerebellum Disorders Archicerebellar Lesion: medulloblastoma Paleocerebellar Lesion: gait disturbance Neocerebellar Lesion: hypotonia, ataxia, tremor