Cerebellum

Coordination of voluntary motor movement and planning of movements

Muscle tone and Cognitive abilities.

Motor activities, balance and equilibrium,

Interpreting touch, vision and hearing

Learning and remembering of physical skills,

Is located anterior to brainstem

Is located superior to cerebrum

Is located dorsally/posterior to the brainstem

Is located inferior to cerebrum

The cerebellum can initiate movements

Although it represents only about 10% of the CNS by volume, it contains roughly 50% of all CNS neurons

The exceedingly large number of input connections to the cerebellum conveys visual and auditory input.

Its folded surface equals to 10% of folded surface of cerebral cortex hemispheres.

The cerebellum controls movement by collecting neural afference from limbs, balance information and vision

It controls proper range, strength and fluent performance

It does not initiate movements itself nor does it take part in their planning and control

Movement is elicited from PNS

The learning of physical tasks is performed then stored in cerebellar memory without correction

All motor functions can be lost with age

Cerebellum is responsible for maintenance of the body balance and upright posture

It establishes proper distribution of the tone to antagonistic muscle in relation to gravity and inertia.

Cerebellar hemispheres

Corpus callosum

Vermis

Flocculo-nodular lobe

Cerebellar peduncles

middle (linkages to pons);

superior (linkages to midbrain, thalamus and cerebral cortex);

middle (linkages to midbrain, thalamus and cerebral cortex);

inferior (indirect linkages to spinal cord through olives).

inferior (linkages to pons);

Afferents originating in pontine nuclei

Afferents originating in reticular formation (reticulocerebellar tract and olivocerebellar tract)

Afferents originating in spinal cord (dorsal spinocerebellar tract)

Afferents from brain stem nuclei to the cerebellar cortex

Bilateral linkages between cerebellum and complex of vestibular nuclei are from cerebellovestibular and vestibulocerebellar tract.

Afferents from brain stem nuclei to the cerebellar cortex.

Afferents originating in spinal cord (dorsal spinocerebellar tract)

Afferents from pontine nuclei with numerous linkages with cerebral cortex

It transmitting impulses between cerebral and cerebellar cortex.

Afferents from brain stem nuclei to the cerebellar cortex.

Fibers of ventral spinocerebellar tract transmitting information from peripheral receptors through spinal cord to cerebellar cortex.

Bilateral linkages between cerebellum and complex of vestibular nuclei – cerebellovestibular and vestibulocerebellar tract

Afferents from pontine nuclei with numerous linkages with cerebral cortex

Efferents from cerebellar nuclei (dentate, emboliform, globose and fastigial nuclei) to nucleus ruber and to thalamus and reticular formation.

Neocerebellum – spinocerebellum (vermis, intermediated area)

Paleocerebellum – spinocerebellum (vermis, intermediated area)

Neocerebellum – corticocerebellum (cerebellar hemispheres)

Archicerebellum – vestibulocerebellum (flocculonodular lobe)

Neocerebellum

Archicerebellum

Vestibulocerebellum

Spinocerebellum

Vestibulocerebellum - Maintenance of balance and control of eye movement

Spinocerebellum - Regulation muscle tone, coordination of skilled voluntary movement

Neocerebellum - Planning and initiation of voluntary activity, storage of procedural movement

Vestibulocerebellum - Regulation muscle tone, coordination of skilled voluntary movement

Made up of the uvula, pyramid and anterior lobe

Located in the flocculonodular lobe, a long cylindrical lobe arching over the 4th ventricle

It helps with the regulation of muscle tone.

Its major function are maintenance of posture and vestibular reflexes.

It helps maintain the body’s balance.

The vestibulocerebellum is related to the vestibular system, with sensors located in the inner ear and whose way stations are located in the pons and medulla.

The archicerebellum is associated with the lateral vestibular nucleus in the brainstem

It receives its strong input from spinal cord afferents (from proximal and distal body parts – spinocerebellar tracts).

It receives its major inputs from vestibular receptors. The major output of this system is to the vestibulospinal tract.

Covers the lateral parts of the cerebellar hemispheres.

Ataxic gait and wide-based standing position,

Intention tremor

Scanning speech

Nystagmus

Dysdiadochokinesia (adiadochokinesia)

Made up of the uvula, pyramid and anterior lobe

The Paleocerebellum is associated with the lateral vestibular nucleus in the brainstem.

Its major function is the control of axial and distal musculature and regulation of muscle tone

Its major function are maintenance of posture

Covers the lateral parts of the cerebellar hemispheres.

It receives its major inputs from vestibular receptors.

The major outputs of this system are to the vestibulospinal, reticulospinal and rubrospinal tracts

It receives its strong input from spinal cord afferents (from proximal and distal body parts –spinocerebellar tracts).

Located in the flocculonodular lobe, a long cylindrical lobe arching over the 4th ventricle

The major outputs of this system are to the to the motor cortex via the ventrolateral nucleus of the thalamus to the motor cortex

The paleocerebellum is associated with the fastigial, globose and emboliform deep cerebellar nuclei.

Associated with the dentate nucleus of deep cerebellar nuclei

Hypotonia

Decomposition of movement

Improper activity of gamma motor neurons.

Delay in the initiation and termination of movements

The major outputs of this system are to the vestibulospinal

Covers the lateral parts of the cerebellar hemispheres.

Its functions include initiation, coordination and timing of fine, voluntary movements

Made up of the uvula, pyramid and anterior lobe

The major outputs of this system are to the motor cortex and premotor cortex through the ventrolateral nucleus of the thalamus.

Associated with the dentate nucleus of deep cerebellar nuclei

The Neocerebellum is associated with the fastigial, globose and emboliform deep cerebellar nuclei.

Located in the flocculonodular lobe, a long cylindrical lobe arching over the 4th ventricle

Dysdiadochokinesia (adiadochokinesia) and scanning speech

Improper activity of gamma motor neurons

Intention tremor and decomposition of movement

Delay in the initiation and termination of movements

Ataxic gait and wide-based standing position

The neocerebellum, the largest part of the human cerebellum

Receives a massive number of projections from sensorimotor portions of the cerebral cortex via neurons in the pons.

It coordinates motor behavior

It receives its strong input from spinal cord afferents (from proximal and distal body parts –spinocerebellar tracts).

It controls its rate, range, force, direction. As well as improving motor skills

It helps in general sensation.

It compares sensory (proproceptive) feedback with neural signals from motor cortex – motor act.

It helps in the auditory process.

It regulates movement, posture and vestibuloocular reflex

Has 3 layers of cells; Molecular, Purkinje & Granular

Has 2 types of fibers - climbing and mossy fibers

Has 1 type of fibers - climbing fibers

Has 2 layers of cells; Molecular, Purkinje

Anterior and posterior spino-cerebellar pathways finish with climbing fibers on granular cells of cerebellar cortex

Mossy fibers of spino-olivo-cerebellar project large piriform (Purkinje) cells of the cerebellar cortex

Climbing fibers of spino-olivo-cerebellar project large piriform (Purkinje) cells of the cerebellar cortex

Anterior and posterior spino-cerebellar pathways finish with mossy fibers on granular cells of cerebellar cortex

Spino-cerebellar paths - finishing (as mossy fibers) Not crossing the midline – posterior, dorsal, Flechsig’s.

Spino-olivary-cerebellar path – finishing (as climbing fibers) on Purkinje cells (crossing the midline twice).

Spino-olivary-cerebellar path – finishing (as climbing fibers) on Purkinje cells (Not crossing the midline – anterior, ventral, Gowers’)

Spino-cerebellar paths - finishing (as mossy fibers) Crossing the midline – posterior, dorsal, Flechsig’s.

Tecto-cerebellar tract (auditory and visual impulses through superior and inferior colliculi)

Nucleo-cerebellar paths – from trigeminal nucleus and NTS.

Vestibulo-cerebellar tract (vestibular organ – vestibular nuclei to cerebellum).

Tecto-cerebellar tract (proprioceptive impulses from head and neck/upper limb)

Cuneo-cerebellar tract (auditory and visual impulses through superior and inferior colliculi)

Reticulo-cerebellar tract.

Tecto-cerebellar tract (from contralateral pons; receiving input from cortex).

Ponto-cerebellar tract (from contralateral pons; receiving input from cortex).

Cuneo-cerebellar tract (proprioceptive impulses from head and neck/upper limb).

Cerebello- thalamo-cortical paths (through VLn of the thalamus).

Reticulo-cerebellar tract.

Cerebello-rubro-thalamo-cortical.

Nucleo-cerebellar paths

Cerebello-rubral and rubro-spinal tract.

Vestibulo-cerebellar tract

Cerebellum influense olivary nuclei through reticular system (regulation related to extrapyramidal system).

Cerebello-vestibular and vestibulo-spinal tract.

Cuneo-cerebellar tract

Cerebellar cortex receives all the cerebellar input (afference) through mossy and climbing fibers.

Cerebellar cortex gives all the cerebellar output (afference) through mossy and climbing fibers.

Cerebellar cortex modulates activity of neurons of deep cerebellar nuclei that project output of cerebellum.

Cerebelar cortex receives all the cerebellar input (afference) through climbing fibers.

Dentate - voluntary movement

Emboliform - posture

Globose - small, precise movement

Fastigial - equilibrium

Dentate - nucleus ruber-thalamus- cortex

Emboliform - contralateral thalamus – cortex

Globose - nucleus ruber, reticular formation– spinal cord

Fastigial - vestibular nuclei –spinal cord, reticulospinal tract

Fastigial nucleus regulates distribution of muscle tone at rest and during physical activity.

Emboliform nucleus controls planning and performance of voluntary movements especially precise and complex

Globose nucleus controls body position.

Dentate nucleus regulates performance of fine, precise movements.

Caused by tumors pressing on areas of the cerebellum, trauma, infection, infarction and metabolic problems.

Chronic reasons lead to sudden and strong initiation of symptoms

An acute reason will lead to sudden and strong initiation of symptoms

Damage to the cerebellum or the cerebellar peduncles is uncommon in multiple sclerosis.

II phase - hypotonia, atonia, ataxia, etc,

I phase - hypotonia, atonia, ataxia, etc,

II phase - temporary elevation of the muscle tone

I phase – temporary elevation of the muscle tone

Hypotonia

Ataxia

Astenia

Hypertonia

Ataxia, abasia. dis-coordination, hypotonia and atonia

Decomposition of movement, scanning speech and astenia

Partial blindness and depth perception

Nystagmus, intention tremor, disdiadochokinesia and adiadochokinesia

Peripheral paralysis, resting tremors and memory loss

Hypo-, hyper-, dysmetria