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Cerebellum Cerebellum
Functional AnatomyFunctional Anatomy
Functions Functions
Disorders Disorders
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Motor cortex
Basal ganglia
Brain Stem
cerebellum
Spinal Cord Skeletal
muscles
Neural centres for control of movements
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CerebellumCerebellum
Associated with all aspects of Associated with all aspects of control of movementscontrol of movements
Its removal produces no deficits Its removal produces no deficits in emotional or intellectual in emotional or intellectual functionsfunctions
Causes profound disturbances in Causes profound disturbances in production of coordinated production of coordinated movementsmovements
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CerebellumCerebellum
Functions in controlling of timing Functions in controlling of timing ofof• Duration and strength of Duration and strength of
movementsmovements• Motor activitiesMotor activities
Rapid progression from one movement Rapid progression from one movement to nextto next
Helps to control the interplayHelps to control the interplay• Between agonist and antagonist Between agonist and antagonist
musclesmuscles
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Cerebellum Cerebellum Human cerebellum consists Human cerebellum consists
• Two lateral hemispheres Two lateral hemispheres • On either side of vermisOn either side of vermis
Corpus cerebellaCorpus cerebella• Anterior & posterior lobesAnterior & posterior lobes
Flocculonodular lobeFlocculonodular lobe• Phylogenetically the oldest partPhylogenetically the oldest part
ArchiecerebellumArchiecerebellum
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Cerebellum Cerebellum
Anterior lobe and part of mid Anterior lobe and part of mid portion of posterior lobeportion of posterior lobe• PaleocerebellumPaleocerebellum
90% of posterior lobe 90% of posterior lobe • RecentRecent• Highly developed in primateHighly developed in primate• NeocerebellumNeocerebellum
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Cerebellum Cerebellum
Anterior lobe
Primary fissure
Posterior lobe
Flocculonodular lobe
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Cerebellum Cerebellum
Longitudinal functional divisionLongitudinal functional division Vermis:Vermis:
• Control muscles of axial body, the neck, Control muscles of axial body, the neck, shoulders, hipsshoulders, hips
• Responsible for balanceResponsible for balance• Regulation of axial and postural musclesRegulation of axial and postural muscles
Intermediate zoneIntermediate zone• Control of muscles of distal portions of Control of muscles of distal portions of
upper and lower limbsupper and lower limbs
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Lateral zoneLateral zone• Planning of sequential movementsPlanning of sequential movements• Timing of motor activitiesTiming of motor activities• Coordination of motor activitiesCoordination of motor activities
Cerebellum Cerebellum
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VermisIntermediate lobe
Lateral Lobe
Anterior Lobe
Primary Fissure
Post. Lobe
Flocculanodular Lobe
Longitudinal Division of cerebellum
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Cerebella InputsCerebella Inputs
From spinal cordFrom spinal cord Spinal cerebella tractSpinal cerebella tract
• Dorsal SCT Dorsal SCT From muscle spindle, Golgi tendon organs, From muscle spindle, Golgi tendon organs,
joint receptors, skinjoint receptors, skin
• Appraise cerebellum of Appraise cerebellum of Muscle contractionMuscle contraction Degree of tension on muscle tendonsDegree of tension on muscle tendons Position and rate of movements of parts of Position and rate of movements of parts of
bodybody
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Cerebella AfferentsCerebella Afferents
Vent. Spin. C.T
Muscles, joints Receptors
Dorsal S.C.T
Spino-cerebella tracts
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Cerebella AfferentsCerebella Afferents
Ventral SCTVentral SCT• Excited by signals arriving in spinal Excited by signals arriving in spinal
cord from CST & RUSTcord from CST & RUST• Provide information to cerebellumProvide information to cerebellum
About the arrival of motor signals at About the arrival of motor signals at spinal cordspinal cord
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Cerebella AfferentsCerebella Afferents
From cerebral cortexFrom cerebral cortex• cortico-cerebella pathwaycortico-cerebella pathway
Motor cortexMotor cortex pons pons cerebellum cerebellum• Mossy fibersMossy fibers
Motor cortexMotor cortexinferior oliveinferior olivecerebellumcerebellum• Climbing fibersClimbing fibers
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Motor cortex
BG
RF
Inferior Olive
From/To spinal cord
Ponto cerebella (mossy fibres)
Olivo cerebella (Climbing fibres
Cerebella cortex
Cortico-cerebella pathways
Pons
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Cerebella InputsCerebella Inputs
From Vestibular apparatusFrom Vestibular apparatus• Vestibular nerve Vestibular nerve Vestibular nucleus Vestibular nucleus
Flocculonodular lobeFlocculonodular lobe• Signals from eyesSignals from eyes
Important for maintenance ofImportant for maintenance of• Equilibrium and balanceEquilibrium and balance
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Premotor area
(Eye movement) Occipital lobe
Superior Colliculus
Pons
Olivary nucleus
Vestibular Nucleus
Vestibular Nerve
Flocculo nodular lobe
Eye
Vestibular Input
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Cerebellum InputsCerebellum Inputs
Motor signals from cortex to Motor signals from cortex to spinal cordspinal cord• Sent to cerebellum via collateralSent to cerebellum via collateral• Cerebellum receivesCerebellum receives
Copy of motor instructions for Copy of motor instructions for Voluntary movements to musclesVoluntary movements to muscles
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Cerebellum InputsCerebellum Inputs
Cerebellum also receivesCerebellum also receives• Information about actual Information about actual
performanceperformance From proprioceptors, joint receptorsFrom proprioceptors, joint receptors
Cerebellum comparesCerebellum compares• Instructions with performanceInstructions with performance• Corrects any discrepanciesCorrects any discrepancies
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Spinal Cord Movements executed by muscles
Cerebellum
BG
RF
Motor cortex
Vestibular apparatus
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Cerebella EfferentCerebella Efferent
Cerebella cortex
DCN
DCN
Deep Cerebella Nuclei: Dentate, Interpositus, Fastigial
Cerebral cortex
Midbrain Nuclei, reticular formation
Spinal cord
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Output from Vermis
Fastigial nucleus
Reticular Formation
Lateral vestibular nucleus (Deiters)
VESTREST
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Motor Cortex
Ventral Lateral/ Anterior Thalamus
Intralaminar nucleus
BG
Interpostus Nucleus
Intermediate zone
CST
Red Nucleus
RUST
Out put from Intermediate lobe
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Motor Cortex
Ventral Lateral/ Anterior Thalamus
Red Nucleus
CSTRUST
Lateral zone
Out put from Lateral Cerebella zone
Dentate Nucleus
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Cerebella CellsCerebella Cells
Purkinje cellsPurkinje cells• Big with extensive networks of dendritesBig with extensive networks of dendrites• Receive excitatory signals fromReceive excitatory signals from
Climbing fibersClimbing fibers Granular cells via parallel fibersGranular cells via parallel fibers
• GlutamateGlutamate
• Receive inhibitory signals fromReceive inhibitory signals from Basket cells Basket cells (GABA)(GABA)
• Axons form the only output from Axons form the only output from cerebella cortexcerebella cortex
GABAGABA
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Cerebella CellsCerebella Cells
Granule cellsGranule cells• Receive inputs fromReceive inputs from
Mossy fibersMossy fibers
• Send signals toSend signals to Purkinje, Golgi, basket cellsPurkinje, Golgi, basket cells GlutamateGlutamate
Golgi cellsGolgi cells• Stimulated by granule cells via parallel Stimulated by granule cells via parallel
fibersfibers• They inhibit the granule cellsThey inhibit the granule cells
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Cerebella (Cells)Cerebella (Cells)
Basket cellsBasket cells• Molecular layerMolecular layer• Stimulated by parallel fibersStimulated by parallel fibers• Inhibition of Purkinje cells Inhibition of Purkinje cells (GABA)(GABA)
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PC
DCNClim
bin
g fi
bers
Mossy fibres
Gran. Cell
BC
GC
++ + +
+
+
+
+
-
-
-
Molecular layer
Purkinje Cell layer
Granular Cell layer
Deep cerebella Nuclei layer
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SummarySummary
Cerebella systemCerebella system• Consists of cerebellum, efferent and Consists of cerebellum, efferent and
afferent connectionsafferent connections Is essential for execution of smooth Is essential for execution of smooth
coordinated movementcoordinated movement Does not exert its effects directly on Does not exert its effects directly on
the musclesthe muscles• Efferent connections are to neurons of Efferent connections are to neurons of
pyramidal and extra pyramidal systempyramidal and extra pyramidal system Effects are mediated through these systemsEffects are mediated through these systems
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Cerebella SystemCerebella System
Information passing down the Information passing down the pyramidal system to the musclespyramidal system to the muscles• Is sent via collateral to the cerebellumIs sent via collateral to the cerebellum• Cerebellum receives a copy of Cerebellum receives a copy of
instructions for voluntary mov. Sent to instructions for voluntary mov. Sent to musclesmuscles
Cerebellum also receives information Cerebellum also receives information about the actual performanceabout the actual performance• From proprioceptor, joint receptors, skinFrom proprioceptor, joint receptors, skin
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Cerebella SystemCerebella System
Cerebellum comparesCerebellum compares• Instructions with performanceInstructions with performance• Any discrepancy is correctedAny discrepancy is corrected
Via efferent pathways to motor systemVia efferent pathways to motor system
Chief characteristics of damage Chief characteristics of damage to cerebella systemto cerebella system• Lack of precession in voluntary Lack of precession in voluntary
movementmovement
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Spinal Cord Movements executed by muscles
cerebellum
BG
RF
Motor cortex
Vestibular apparatus
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Lesion of one cerebella Lesion of one cerebella hemispherehemisphere• Leads to dysfunction of limbs on Leads to dysfunction of limbs on
the same sidethe same side Midline cerebella structure Midline cerebella structure
lesionlesion• Disturbances of equilibrium in Disturbances of equilibrium in
upright postureupright posture• Ataxia of stance and gaitAtaxia of stance and gait
Broad based gaitBroad based gait Tendency to fall to either sideTendency to fall to either side Difficult in stopping suddenly or turningDifficult in stopping suddenly or turning
Disorders of CerebellumDisorders of Cerebellum
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Disorders of CerebellumDisorders of Cerebellum
More laterally placed cerebella More laterally placed cerebella lesionslesions• Voluntary movement disturbancesVoluntary movement disturbances• Cerebella ataxiaCerebella ataxia
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Cerebella AtaxiaCerebella Ataxia
Disturbances of voluntary Disturbances of voluntary movementsmovements• Un coordinated or clumsinessUn coordinated or clumsiness• Movements are badly dampedMovements are badly damped
Slow to startSlow to start Slow to stopSlow to stop
• Sequences of movements are Sequences of movements are disjointeddisjointed
Decomposition of movementsDecomposition of movements Ataxia is not made worse by closure of Ataxia is not made worse by closure of
eyeseyes
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ManifestationsManifestations
DysdiadochokinesiaDysdiadochokinesia• Inability to make repeated Inability to make repeated
movementsmovements DysmetriaDysmetria
• Inability to execute correct range of Inability to execute correct range of voluntary movements with voluntary movements with precisionprecision
• Past pointingPast pointing
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ManifestationsManifestations
Intentional tremorsIntentional tremors• Coarse irregular tremors as limb Coarse irregular tremors as limb
approaches targetapproaches target• Badly damped movementsBadly damped movements• Oscillate around targetOscillate around target
Pendular knee jerksPendular knee jerks• Rebound phenomenonRebound phenomenon