july 2, 2015july 2, 2015july 2, 2015 cerebellum 1 cerebellum functional anatomy functionsdisorders

April 19, 2023April 19, 2023 CerebellumCerebellum 11

Cerebellum Cerebellum

Functional AnatomyFunctional Anatomy

Functions Functions

Disorders Disorders


Motor cortex

Basal ganglia

Brain Stem

cerebellum

Spinal Cord Skeletal

muscles

Neural centres for control of movements


Cerebellum


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


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


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



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



Anterior lobe

Primary fissure

Posterior lobe

Flocculonodular lobe



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


Lateral zoneLateral zone• Planning of sequential movementsPlanning of sequential movements• Timing of motor activitiesTiming of motor activities• Coordination of motor activitiesCoordination of motor activities



VermisIntermediate lobe

Lateral Lobe

Anterior Lobe

Primary Fissure

Post. Lobe

Flocculanodular Lobe

Longitudinal Division of cerebellum


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


Cerebella AfferentsCerebella Afferents

Vent. Spin. C.T

Muscles, joints Receptors

Dorsal S.C.T

Spino-cerebella tracts



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



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


Motor cortex

BG

RF

Inferior Olive

From/To spinal cord

Ponto cerebella (mossy fibres)

Olivo cerebella (Climbing fibres

Cerebella cortex

Cortico-cerebella pathways

Pons


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


Premotor area

(Eye movement) Occipital lobe

Superior Colliculus

Pons

Olivary nucleus

Vestibular Nucleus

Vestibular Nerve

Flocculo nodular lobe

Eye

Vestibular Input


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


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


Spinal Cord Movements executed by muscles

Cerebellum

BG

RF

Motor cortex

Vestibular apparatus


Cerebella EfferentCerebella Efferent

Cerebella cortex

DCN

DCN

Deep Cerebella Nuclei: Dentate, Interpositus, Fastigial

Cerebral cortex

Midbrain Nuclei, reticular formation

Spinal cord


Output from Vermis

Fastigial nucleus

Reticular Formation

Lateral vestibular nucleus (Deiters)

VESTREST


Motor Cortex

Ventral Lateral/ Anterior Thalamus

Intralaminar nucleus

BG

Interpostus Nucleus

Intermediate zone

CST

Red Nucleus

RUST

Out put from Intermediate lobe


Motor Cortex

Ventral Lateral/ Anterior Thalamus

Red Nucleus

CSTRUST

Lateral zone

Out put from Lateral Cerebella zone

Dentate Nucleus


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


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


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)


PC

DCNClim

bin

g fi

bers

Mossy fibres

Gran. Cell

BC

GC

++ + +

+

+

+

+

-

-

-

Molecular layer

Purkinje Cell layer

Granular Cell layer

Deep cerebella Nuclei layer


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


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


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


Spinal Cord Movements executed by muscles

cerebellum

BG

RF

Motor cortex

Vestibular apparatus


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


Disorders of CerebellumDisorders of Cerebellum

More laterally placed cerebella More laterally placed cerebella lesionslesions• Voluntary movement disturbancesVoluntary movement disturbances• Cerebella ataxiaCerebella ataxia


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


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



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



DysarthriaDysarthria• Speech disordersSpeech disorders

NystagmusNystagmus• Eye movements poorly dampedEye movements poorly damped• Oscillate around targetOscillate around target

HypotoniaHypotonia

july 2, 2015july 2, 2015july 2, 2015 cerebellum 1 cerebellum functional anatomy functionsdisorders

Documents

cerebellum human cerebellum

cerebellum functions

posterior lobe recentrecent

control of movements

antagonist muscles slide

lateral zone lateral

aspects of control

timing of functions