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