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The Cerebellum.

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Presentation on theme: "The Cerebellum."— Presentation transcript:

1 The Cerebellum

2 Position Lies above and behind the medulla and pons and occupies posterior cranial fossa Its surface is high convoluted, forming folds or folia, being oriented transversely Cerebellum

3 External features Consists of two cerebellar hemisphere united in the midline by the vermis

4 External features Three peduncles
Inferior cerebellar peduncle -connect with medulla and with spinal cord, contain both afferent and efferent fibers Middle cerebellar peduncle -connect with pons, contain afferent fibers Superior cerebellar peduncle -connect with midbrain, contain mostly efferent fibers


6 External features Tonsil of cerebellum two elevated masses on inferior surface of hemispheral portion just nearby foramen magnum

7 Lobes Two deep fissures Three lobs Primary fissure
Uvulonodular fissure Three lobs Flocculonodular lobe Anterior Posterior lobe

8 Lobes Anterior lobe corpus of cerebellar Primary fissure
Posterior lobe Flocculonodular lobe Posterolateral fissure


10 Internal structures White matter Gray matter Cerebellar cortex
Cerebellar nuclei Dentate nucleus Fastigial nucleus Emboliform nucleus Globose nucleus White matter

11 Internal structures Fastigial nucleus Cerebellar cortex
Globose nucleus Dentate nucleus Emboliform nucleus medullary center

12 Deep Nuclei 1. fastigial nucleus 2. globose 3. emboliform 4. dentate

13 Three functional divisions
Vestibulocerebellum Archicerebellum Flocculonodular lobe Spinocerebellum Paleocerebellum Vermis and intermediate zone Cerebrocerebellum Neocerebellum Lateral zone Vermis Intermediate zone Lateral zone Flocculonodular lobe

14 Cerebellar divisions Spinocerebellum: Vermis Intermediate hem.
(Vermis + Intermed. Hem) Control of limbs and trunk Lateral hem. Cerebrocerebellum: Cerebrocerebellum (Lateral hemisphere) Planning of movement+ IVth vent Floculo-nodular lobe Vestibulo-cerebellum (Floculo-nodular lobe) Control of eye & head movements Balance

15 Connections and function of cerebellum
Vestibulocerebellum Connections Afferents: receive input from vestibular nuclei and inner ear. Efferents: projects to the vestibular nucleus → vestibulospinal → motor neurons of anterior horn Function: involved in eye movements and maintain balance


17 Connections and function of cerebellum
Spinocerebellum Connnection Afferents: receive somatic sensory information via spinocerebellar tracts

18 Efferents: Fastigeal reticular and fastigial vestibular pathways: Vermis projects to the fastigial nucleus → vestibular nuclei and reticular formation → vestibulospinal tract and reticulospinal tract → motor neurons of anterior horn Intermediate zone projects to the interposed nuclei Globose- emboliform-rubral pathway: Contralateral red nucleus → rubrospinal tract →motor neurons of anterior horn Function: play an important role in control of muscle tone and coordination of muscle movement on the same side of the body


20 Connections and function of cerebellum
Cerebrocerebellum Connection Afferents: receives input from the cerebral cortex via a relay in pontine nuclei(corticopontocerebellar pathway) Efferents: (dentothalamic pathway): dentate nucleus → contralateral thalamus → primary motor cortex → corticospinal tract → motor neurons of anterior horn Function: participates in planning movements



23 summary Cerebellar efferent fibers: Globose-emboliform-rubral pathway
Dentothalamic pathway Fastigial reticular pathway Fastigial vestibular pathway

24 summary Cerebellar afferent fibers:
Afferent fibers from cerebral cortex: corticopontocerebellar pathway. Afferent fibers from spinal cord: Anterior and posterior spinocerebellar tracts Afferent fibers from vestibular nerve

25 Pyramidal Tract and Associated Circuits
upper motor neuron UMN Cerebellum BASAL GANGLIA pyramidal tract lower motor neuron UMN

26 Cerebellum Function  Maintenance of Equilibrium
- balance, posture, eye movement  Coordination of movement of walking and posture maintenance - posture, gait  Adjustment of Muscle Tone  Motor Learning – Motor Skills

27 Balance

28 Motor Skill Pablo Casals

29 Cerebellum Clinical Syndromes
1-Ataxia: incoordination of movement - decomposition of movement - tremor - past-pointing 2- dysdiadochokinesia 3-Hypotonia, Nystagmus 4- dysarthria

30 Posture Gait – Ataxia

31 Cerebellar Ataxia a b c d Ataxic gait and position:
Left cerebellar tumor a. Sways to the right in standing position b. Steady on the right leg c. Unsteady on the left leg d. ataxic gait d

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