lectures of Neuroanatomy for second year Medical students by Dr. Noura El Tahawy

1. Cerebellum
By
Dr. Noura El Tahawy

2. Magnetic resonance images of the cerebellum of a 16-year-old
female. A, sagittal slice.

3. Magnetic resonance images of the cerebellum of a 16-year-old female.
coronal slice. C,

4. Horizontal section through the cerebellum and brain stem.

5. Lobs
Three deep fissures
Primary fissure
Horizontal fissure
Posterolateral fissure
Three lobs
Flocculonodular lobe
flocculus and nodule
Anterior lobe
Posterior lobe

6. Lobs
Anterior lobe
corpus of
Primary fissure cerebellum
Posterior lobe
Flocculonodular lobe
Posterolateral fissure

7. Cerebellum .A Viewed from above B Viewed from the position of the pons .

8. A Sagittal section of hindbrain .B Oblique section of cerebellum .

9. Internal
structure
Gray matter
Cerebellar cortex
Cerebellar Medulla (White matter)
Cerebellar nuclei
Dentate nucleus, Fastigial nucleus, Interposed
nucleus Emboliform nucleus
Globose nucleus

10. Internal structure
Cerebellar cortex Fastigial nucleus
Dentate nucleus Emboliform nucleus
Globose nuclei
medullary center

11. Cerebellum
Cerebellum Internal Configurations
Internal Configurations
Cerebellar Cortex
Molecular Layer
Purkinje Cell Layer
Granular Layer
Corpus Medullare (Medullary Center)
Deep Cerebellar Nuclei
Fastigial Nuclei
Emboliform Nucleus
Globose Nucleus
Dentate Nucleus

12. Transverse sections of cerebellar folia
Transverse sections of cerebellar folia showing the layers of the cerebellar
cortex.

13. The cerebellar cortex
Diagram shows afferent and efferent connections and their relationships to
the principal cells of the cerebellar cortex.

14. Cerebellar cortex .A Cell layers B Afferent system .C Internuncial neurons .D
Efferent system .

15. Three Anatomical Divisions

17. Three functional divisions

18. Schematic drawing of the cerebellum in which the peduncles have been cut and the surface flattened
out. The relationships between the anatomical and functional divisions of the cerebellum are shown.
(Green, archicerebellum; blue, paleocerebellum; pink, neocerebellum.)

19. Three functional divisions
The archicerebellum corresponds to the flocculonodular lobe and
fastigial nucleus. Its principal connections are with the vestibular and
reticular nuclei of the brain stem and it is concerned with the
maintenance of equilibrium.
The paleocerebellum corresponds to the vermis and paravermal area,
together with the globose and emboliform nuclei. It receives fibres
from the spinocerebellar tracts and projects to the red nucleus of the
midbrain.
The neocerebellum corresponds to most of the cerebellar hemisphere
and the dentate nucleus. It receives afferents from the pons and
projects to the ventral lateral nucleus of the thalamus .

20. Connections & functions of the
cerebellum

21. Vestibulocerebellum

22. Summary of Main Connections of the
Summary of Main Connections of the
Vestibulocerebellum
Vestibulocerebellum
Vestibular
Organ
Floculonodular
Lobe Cortex
VESTIBULAR NUCLEUS
vestibulospinal
& Reticulospinal tracts
MLF FASTIGIAL
NUCLEUS
lower motor neuron ARCHICEREBELLUM
LMN

23. Connections of the
Vestibulocerebellum
(archi-cerebellum).
(Contralateral projections of the fastigial nucleus are not shown).

24. Connections and function of Vestibulocerebellum
The archicerebellum is primarily concerned with the maintenance of balance
(equilibrium).
It recieves afferents from the vestibular and reticular nuclei of the brain stem,
passing through the inferior cerebellar peduncles.
Vestibular information is then carried from the vestibular nuclei to the cortex of the
ipsilateral flocculonodular lobe. Cortical cerebellar efferent (Purkinje cell) fibres
project to the fastigial nucleus, which, in turn, projects back to the vestibular nuclei
and to the reticular formation.
A significant proportion of fastigial efferents cross to the contralateral side of the
brain stem.
The influence of the archicerebellum upon the lower motor system is, therefore,
bilateral and principally mediated by means of descending vestibulospinal and
reticulospinal projections (both end in AHCs of spinal cord).
Function: involved in eye movements and maintain balance

25. Spinocerebellum

26. Summary of Main Connections of the
Summary of Main Connections of the
Paleocerebellum
Paleocerebellum
RED NUCLEUS
INTERPOSITUS
NUCLEUS
rubrospinal
tract Inferior
Olivary PALEOCEREBELLAR
PALEOCEREBELLAR
Cortex
Cortex
Nucleus
lower motor neuron
SPINAL CORD spinocerebellar
tracts
(The Start)

27. Connections of the
Spinocerebellum
(Paleocerebellum)

28. Connections and function of Spinocerebellum
(Paleocerebellum)
The paleocerebellum influences muscle tone and posture.
Afferents consist principally of dorsal and ventral spinocerebellar tract neurones
that carry information from muscle, joint and cutaneous receptors and enter the
cerebellum through the inferior and superior cerebellar peduncles, respectively
Fibres terminate largely in the cortex of the ipsilateral vermis and paravermis.
Cerebellar cortical efferents from these areas pass to the globose and emboliform
nuclei and also to the fastigial nucleus.
The globose and emboliform nuclei project via the superior cerebellar peduncle to
the contralateral red nucleus of the midbrain, where they influence the activity of
cells giving rise to the descending rubrospinal tract .

29. Neocerebellum

30. Summary of Main Connections of the
Summary of Main Connections of the
Neocerebellum
Neocerebellum
CEREBRAL
CEREBRAL THALAMUS
THALAMUS DENTATE
DENTATE
CORTEX
CORTEX LV nucleus
LV nucleus NUCLEUS
NUCLEUS
Red nucleus
pyramidal
tract
NEOCEREBELLAR
NEOCEREBELLAR
Pontine
Pontine Cortex
Cortex
Nucleus
Nucleus
lower motor neuron
LMN

31. Connections of the Neocerebellum.

32. Connections and function of Neocerebellum
The neocerebellum is concerned with muscular coordination, including the trajectory, speed and force of movements.
The principal afferent pathway consists of pontocerebellar fibers . (These originate in the pontine nuclei of the basal
portion of the pons and cross to the opposite side, entering the cerebellum through middle cerebellar peduncle
peduncle.
Pontocerebellar neurons are influenced by widespread regions of the cerebral cortex involved in the planning and
execution of movement. Pontocerebellar fibres terminate predominantly in the lateral parts of the cerebellar
hemisphere.
Output from the neocerebellar cortex is directed to the dentate nucleus. The dentate nucleus, in turn, projects to the
contralateral red nucleus and ventral lateral nucleus of the thalamus. The dentate is the largest of the cerebellar nuclei
and its efferents form a major part of the superior cerebellar peduncle.
The fibres decussate in the caudal midbrain just before reaching the red nucleus. Some relay in the red nucleus with
rubrothalamic cells but most bypass the red nucleus and pass directly to the ventral lateral thalamus.
The ventral lateral nucleus of the thalamus projects to the cerebral cortex, particularly the motor cortex of the frontal
lobe.
The neocerebellum thus exerts its coordinating role in movement primarily through an action on cerebral cortical
areas, giving rise to descending corticospinal and corticobulbar pathways .

33. Principal cerebellar efferents.
Arrows indicate directions of impulse conduction.

34. Summary
Summary
Cerebellum and Automatic Motor Control
Cerebellum and Automatic Motor Control
Motor Cortex
Motor Cortex
CEREBELLUM
CEREBELLUM
Red Nucleus
Red Nucleus
Reticular Vestibular
Vestibular
Reticular
Formation Nucleus
Nucleus
Formation
Lower Motor Neuron (LMN)
Lower Motor Neuron (LMN) Proprioceptors
Proprioceptors

35. Functions of the cerebellum
Maintenance of Equilibrium
- balance, posture, eye movement
Coordination of half-automatic movement of
walking and posture maintenance
- posture, gait
Adjustment of Muscle Tone
Motor Learning – Motor Skills
Cognitive Function

36. Functions of the cerebellum
Balance

37. Functions of the cerebellum
Motor Skills
Pablo Casals
Pablo Casals

38. Cerebellar Syndrome
From this information the cerebellum coordinates the range, velocity and
strength of contractions to produce steady volitional movements and
steady volitional postures.
Incoordination (ataxia) is the main feature of cerebellar dysfunction. An
easy way to remember a cerebellar syndrome is to imagine a drunken
person who cannot coordinate any volitional movement. He sways when
standing, reels when walking, slurs words when talking and has jerky
eye movements when looking.
In addition, the muscles are loose and floppy (hypotonia).
Thus, ataxia, dysarthria, nystagmus and hypotonia are the four
major clinical signs of the cerebellar syndrome.

39. Posture
Gait – Ataxia
Tremor

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

41. Cerebellar
Medulloblastoma
Cerebellar tumors on vermis
- Truncal Ataxia
- Frequent Falling
The child in this picture:
- would not try to stand
unsupported
- would not let go of the bed rail
if she was stood on the floor.

42. Cerebellar Peduncles

43. Lateral aspect of the brain stem and cerebellum, showing the cerebellar
peduncles .Parts of the anterior, posterior and flocculonodular lobes have been
removed to display the peduncles more clearly .

44. Anteroinferior aspect of the cerebellum, Showing the three cerebellar peduncles

45. Anteroinferior aspect of the cerebellum., Showing the three cerebellar peduncles

46. Dissection of the left cerebellar hemisphere and its peduncles.

47. Diagram illustrating the composition of the cerebellar peduncles. A, dorsal
view. B, lateral view.
Downloaded from: Gray's Anatomy (on 25 July 2009 06:36 AM)
© 2007 Elsevier

48. Tractology of the cerebellum
(Cerebellar Peduncles)
Inferior cerebellar Middle cerebellar Superior cerebellar
peduncles peduncles peduncles
Afferents 1. Posterior 1. Pontocerebellar 1. Anterior
spinocerebellar spinocerebellar
2. Cuneo-cerebellar 2. Tecto-cerebellar
(posterior external
actuate fibers)
3. Olivo-cerebellar
4. Parolivo-cerebellar
5. Vestibulo-cerebellar
6. Reticulo-cerebellar
7. Anterior external
arcuate fibers
Efferents 1. Cerebello-olivary 1. Cerebello- 1. Dentato-rubral
2. Cerebello-vestibular pontine 2. Dentato-thalamic
3. Cerebello-reticular (LVN)
3. Dentato-olivary
4. Dentato-reticular

49. Blood Supply of the cerebellum
The posterior inferior cerebellar artery (from
vertebral artery) supplies the cerebellum &the
side of the medulla
The anterior inferior cerebellar and superior
cerebellar arteries (both arise from basilar
artery) supply the cerebellum& side of the pons

51. The arteries on the base of the brain.

52. Thanks
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