cerebellum ppt

DR NILESH KATE

MBBS,MDASSOCIATE PROF

ESIC MEDICAL COLLEGE, GULBARGA. DEPT. OF PHYSIOLOGY

CEREBELLUM

OBJECTIVES

Physiological Anatomy Neural circuits & neuronal activity Connections Functions Applied physiology.

Cerebellum. Largest part of hind brain. Called “silent area.” Weight- 150 gms.

Friday, January 16, 2015

Physiological anatomy. External features . Anatomical parts. Anatomical divisions. Phylogenetically divisions. Functional divisions. Histological structure.


External features

Surfaces . Folia.- transverse

folds Fissures.

Primary Horizontal Posterolateral.


Anatomical parts Parts of vermis.

Lingula Central lobule Culmen Declive Folium Tuber Pyramis Uvula Nodule.

Parts of hemisphere. No lateral projection. Alae Anterior quadrangular lobule Posterior quadrangular

lobule Superior semilunar lobule Inferior semilunar lobule. Biventral lobule Tonsil Flocculus.


Anatomical divisions

Anterior lobe. Posterior lobe. Flocculonodular lobe..


Phylogenetically divisions

Archicerebellum Floculonodular lobe Lingula

Paleocerebellum Anterior lobe except – lingula Posterior lobe – pyramis, uvula & paraflocculus.

Neocerebellum. Whole posterior lobe except –pyramis & uvula.


Functional divisions. Vestibulocerebellum.

Consists of Floculonodular lobe

Vestibular connections N. fastigeal – effector N. Control body posture &

equilibrium.

Spinocerebellum. Consists of

Paleocerebellum. N Interpositus. – effector N. Postural reflexes.

Corticocerebellum. Central cerebellum Dentate N.- effector

nucleus. Smooth performance.


Functional divisions.


Histological structure. Cerebellar cortex.

Molecular layer. Purkinje cell layer. Granule cell layer.

White matter. Projection fibres. Association fibres. Commissural fibres.

Deep cerebellar nuclei. Dentate nucleus. Emboliform nucleus. Globossus nucleus. Fastigeal nucleus.


Histological structure.


Cerebellar cortex.

Molecular layer. Stellate cells Basket cells.

Purkinje cell layer. Granule cell layer.

Granule cells Golgi cells.


Cerebellar cortex.


Sensory inputs. Climbing fibres

Inferior olivary nucleus

Cerebellum.( purkinje cells)

Mossy fibres. Spino, vestibulo,

reticulo, cuneo & corticoponto

Cerebellum(Glomerulus)


Olivocerebellar tract.

Sensory inputs.


White matter. Projection fibres. Association fibres.

Commissural fibres.


Deep Cerebellar Nuclei. Dentate nucleus. Emboliform

nucleus. Globossus nucleus. Fastigeal nucleus.Near roof of IV

ventricle.


Neural circuits & neuronal activity.

Afferents of cerebellar cortex. Climbing Fibres. Mossy Fibres.

Neuronal activity of deep cerebellar circuits Feed forward inhibition of purkinje cells. Feed forward inhibition of Granule cells. Feed back inhibition of Granule cells. The reverberating circuits. Neuronal activity of deep cerebellar nuclei.


Afferents of cerebellar cortex.

Climbing Fibres. Mossy Fibres.


Neuronal activity of deep cerebellar circuits

Feed forward inhibition of Purkinje cells. Mossy fibres Granule cells

Purkinje cells. Basket cells. Feed forward inhibition of Granule cells.Mossy fibres Granule cells.

Golgi cells Feed back inhibition of Granule cells.


Neuronal activity of deep cerebellar neuclei.Cerebral cortex motor

pathway.spinal cord.

Thalamus brainstem nuclei.

Deep cerebellar nuclei.

Climbing fibres, mossy fibres.


Connections of cerebellum.

Cerebellar Peduncles.. Inferior

Afferents Dorsospinocerebellar. External arcuate

fibres. Vestibulocerebellar

tract. Oliocerebellar tract. Reticulocerebellar

tract.

Middle. Afferents. – cerebro-

pontine – cerebellar.

Superior Afferent –

Tectocerebellar Ventral

spinocerebellar Efferent –

Dentorubral Dentothalamic Mid-brain.


Afferent connections Dorsal spinocerebellar tract. (external) Ventral spinocerebellar tract. (Internal) Cuneocerebellar tract.

From accessory cuneate N. Olivocerebellar tract.

From brainstem, SC, cortex


Afferent connections

Cortico-ponto-cerebellar tract. Tectocerebellar tract.From superior colliculi (visual impulses)&

inferior colliculi (auditory impulses)of tectum of mid brain.

Vestibulocerebellar tract. (position & movement of head)

Rubrocerebellar tract. ( from motor cortex ) Reticulocerebellar tract.Friday, January 16, 2015

Afferent connections


Localization of sensory impulses to cerebellum.


Efferents connections. Dento-rubro-thalamo-

cortical pathway. Cerebello-thalamic-

cortical pathway. Cerebelloreticular

pathway. Cerebellovestibular

fibres.

Cerebello-olivary fibres.

Oculomotor nerve & tectum.


Efferent connections.


Functions of cerebellum. Control of body posture & equilibrium. Control of muscle tone & stretch reflex. Control of voluntary movements.


Control of body posture & equilibrium.


Control of muscle tone & stretch reflex.


Control of voluntary movements.


Mechanism of action. Comparator function. Damping action. Timing & programming the movements. Control of ballistic movements. Servomechanism.


Comparator function.


Other functions of cerebellum. Autonomic system (through Hypothalamus &

reticular formation.) Ascending sensory pathway. (through

reticular formation & thalamus) Eyeball movements. ( through vestibular

nuclei)


Cerebellar lesions. Common causes. Signs of cerebellar dysfunction. Tests .


Common causes. Vascular occlusions (thrombosis) Tumor Injuries.


Signs of cerebellar dysfunction. Tone & posture disturbance

Atonia or hypotonia Attitude changes.

Rotation of face to opposite side Lowering of shoulder. Outward rotation & abduction of leg.

Deviation movements. Effect on deep reflexes. (weak & pendular)


Signs of cerebellar dysfunction.

Equilibrium disturbance. (drunken gait) Movements disturbance.

Ataxia Intention tremors Nystagmus. Dysarthria. Astasia.


Clinical tests of cerebellar dysfunction.

Upper limb Finger nose test Diadokokinesia. Rebound phenomenon. Past pointing.

Lower limb. Rombergs test. Tandem gait.


Tests .


Thank You

cerebellum ppt

Health & Medicine

projection fibres

commissural fibres

association fibres

purkinje cellsmossy

granule cellsgolgi cells

afferents of cerebellar

cerebellar peduncles

external arcuate fibres