The document provides an overview of the cerebellum including its: - Physiological anatomy, divisions, and histological structure - Neural circuits and neuronal activity - Connections with other parts of the brain and spinal cord - Key functions in controlling posture, balance, muscle tone, and voluntary movement - Effects of cerebellar lesions and clinical tests used to assess cerebellar dysfunction

1. DR NILESH KATE
MBBS,MD
ASSOCIATE PROF
ESIC MEDICAL COLLEGE, GULBARGA.
DEPT. OF PHYSIOLOGY
CEREBELLUM

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

3. Cerebellum.
 Largest part of hind brain.
 Called “silent area.”
 Weight- 150 gms.
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4. Physiological anatomy.
 External features .
 Anatomical parts.
 Anatomical divisions.
 Phylogenetically divisions.
 Functional divisions.
 Histological structure.
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5. External features
 Surfaces .
 Folia.- transverse
folds
 Fissures.
 Primary
 Horizontal
 Posterolateral.
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6. 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.
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7. Anatomical divisions
 Anterior lobe.
 Posterior lobe.
 Flocculonodular lobe..
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8. Phylogenetically
divisions
 Archicerebellum
 Floculonodular lobe
 Lingula
 Paleocerebellum
 Anterior lobe except – lingula
 Posterior lobe – pyramis, uvula & paraflocculus.
 Neocerebellum.
 Whole posterior lobe except –pyramis & uvula.
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10. 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.
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11. Functional divisions.
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12. 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.
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13. Histological structure.
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14. Cerebellar cortex.
 Molecular layer.
 Stellate cells
 Basket cells.
 Purkinje cell layer.
 Granule cell layer.
 Granule cells
 Golgi cells.
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15. Cerebellar cortex.
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16. Sensory inputs.
 Climbing fibres
 Inferior olivary nucleus
 Cerebellum.
( purkinje cells)
 Mossy fibres.
 Spino, vestibulo,
reticulo, cuneo &
corticoponto
 Cerebellum
(Glomerulus)
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Olivocerebellar tract.

17. Sensory inputs.
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20. White matter.
 Projection fibres.  Association fibres.
 Commissural fibres.
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21. Deep Cerebellar Nuclei.
 Dentate nucleus.
 Emboliform
nucleus.
 Globossus nucleus.
 Fastigeal nucleus.
Near roof of IV
ventricle.
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22. Friday, January 16, 2015

23. 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.
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26. Afferents of cerebellar cortex.
 Climbing Fibres.  Mossy Fibres.
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27. 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.
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28. Neuronal activity of deep
cerebellar neuclei.
Cerebral cortex motor
pathway.
spinal cord.
Thalamus brainstem nuclei.
Deep cerebellar nuclei.
Climbing fibres, mossy fibres.
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29. 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.
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30. Friday, January 16, 2015

31. Afferent connections
 Dorsal spinocerebellar tract. (external)
 Ventral spinocerebellar tract. (Internal)
 Cuneocerebellar tract.
From accessory cuneate N.
 Olivocerebellar tract.
From brainstem, SC, cortex
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32. 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.
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33. Afferent connections
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34. Localization of sensory
impulses to cerebellum.
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35. Efferents connections.
 Dento-rubro-thalamo-
cortical pathway.
 Cerebello-thalamic-
cortical pathway.
 Cerebelloreticular
pathway.
 Cerebellovestibular
fibres.
 Cerebello-olivary
fibres.
 Oculomotor nerve &
tectum.
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36. Efferent connections.
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38. Functions of cerebellum.
 Control of body posture & equilibrium.
 Control of muscle tone & stretch reflex.
 Control of voluntary movements.
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39. Control of body posture &
equilibrium.
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40. Control of muscle tone &
stretch reflex.
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41. Control of voluntary movements.
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42. Mechanism of action.
 Comparator function.
 Damping action.
 Timing & programming the movements.
 Control of ballistic movements.
 Servomechanism.
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43. Comparator function.
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44. Other functions of cerebellum.
 Autonomic system (through Hypothalamus &
reticular formation.)
 Ascending sensory pathway. (through
reticular formation & thalamus)
 Eyeball movements. ( through vestibular
nuclei)
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45. Cerebellar lesions.
 Common causes.
 Signs of cerebellar dysfunction.
 Tests .
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46. Common causes.
 Vascular occlusions (thrombosis)
 Tumor
 Injuries.
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47. 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)
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48. Signs of cerebellar dysfunction.
 Equilibrium disturbance. (drunken gait)
 Movements disturbance.
 Ataxia
 Intention tremors
 Nystagmus.
 Dysarthria.
 Astasia.
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49. Clinical tests of cerebellar
dysfunction.
 Upper limb
 Finger nose test
 Diadokokinesia.
 Rebound phenomenon.
 Past pointing.
 Lower limb.
 Rombergs test.
 Tandem gait.
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50. Tests .
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51. Thank
You