The document discusses the anatomy and functions of the cerebellum. It begins by outlining the embryonic development and subdivision of the nervous system. It then describes the three functionally distinct regions of the cerebellum - the vestibulocerebellum, spinocerebellum, and cerebrocerebellum - and their different inputs and outputs. The document also discusses the cerebellar peduncles, cortex, and nuclei. It outlines the roles of the cerebellum in motor control and coordination and describes clinical signs of cerebellar dysfunction such as ataxia.

1. Cerebellum
Lecture Class by
Pratap Sagar
Tiwari, MD, Lecturer, NGMC

2. Nervous System Development :
Anatomical subdivisions
Source : http://en.wikipedia.org/wiki/File:EmbryonicBrain.svg
Reference: Gray’s Anatomy

3. Nervous System Development :
Anatomical subdivisions
Primary division of
neural tube
Sec. subdivision
Final segments
Prosencephalon
1. Telencephalon
2. Diencephalon
1. The cortex,
Caudate, Putamen, Globus pallidus
2.
Thalamus, hypothalamus, subthalamus,
subthalamic nuclei
Mesencephalon
Rombencephalon
Mesencephalon
1. Metencephalon
2. Myelencephalon
Mesencephalon (Midbrain),
Substantia nigra pars compacta
(SNc), Substantia nigra pars reticulata
(SNr)
1. Pons and cerebellum
2. Medulla

4. The Cerebellum Has Three Functionally Distinct Regions
The cerebellum is divided into anatomically distinct lobes.
The main body of cerebellum has three functional regions: the central vermis and the lateral and
intermediate zones in each hemisphere.
It is divided by the primary fissure into anterior and posterior lobes. The posterolateral fissure separates
the flocculonodular lobe.

6. Cerebellum & its connections
Connections with brainstem:
• Superior cerebellar peduncle connects to
midbrain
• Middle cerebellar peduncle connects to pons
• Inferior cerebellar peduncle connects to
medulla

7. Afferent connections with spinal cord
and brain
Afferent connections with spinal cord and
brain
Cortico-cerebellar projection
Ventral spinocerebellar tract
Dorsal spinocerebellar tract

8. Efferent connections
Efferent connections
Thalamus
Red nucleus
Reticular formation
Vestibular nucleus

9. Sections of the Cerebellum
Vestibulocerebellum or archicerebellum
• Comprises the flocculonodular lobe
• Extensive connections with the vestibular system
Spinocerebellum or paleocerebellum
• Comprises the vermis (medial) & paravermal (intermediate)
region
• Extensive connections with the spinal cord & brainstem
Cerebrocerebellum or neocerebellum
• Comprises lateral portions of cerebellar hemispheres
(excluding paravermal regions)
• Extensive connections with cerebral cortex through relay
stations in cerebellar nuclei and dorsal thalamus

10. CEREBELLAR PEDUNCLES

11. Superior cerebellar peduncle
(brachium conjunctivum)
• Connects to midbrain
Afferents: only ventral spinocerebellar tract
Efferents:
• Most of the efferents from the cerebellum
• All of the efferents from three (out of four)
pairs of nuclei: dentate, emboliform, and
globose

12. Middle cerebellar peduncle
(brachium pontis)
• Connects to pons
Afferents: from cerebral cortex (“corticopontocerebellar system”).
Corticopontine projections (originating in the
cerebral cortex) synapse in ipsilateral basal
pons.
From there, most pontocerebellar
projections decussate, pass through middle
cerebellar peduncle and enter cerebellum.
• A small number remain ipsilateral.
Efferents: none.

13. Inferior cerebellar peduncle (“corpus
restiform” or “restiform body”)
• Connects to medulla
• Two components:
• Restiform body
– Afferents:
• Ascending spinal proprioceptive fibers from three of the spinocerebellar tracts
(dorsal, rostral, and cuneocerebellar)
• Ascending fibers from contralateral inferior olivary nuclei to cerebellar cortex
(olivocerebellar projections)
• Reciprocal connections with motor reticular formation and spinocerebellum
(paleocerebellum): reticulocerebellar and cerebelloreticular projections
• Juxtarestiform body
– Mostly
contains
reciprocal
connections
to
and
from
vestibulocerebellum (archicerebellum) and vermal portion of
spinocerebellum
(paleocerebellum):
vestibulocerebellar
and
cerebellovestibular fibers

14. Cerebellar Cortex
Deep Cerebellar Nuclei:
Dentate
Interposed
Fastigial
PNS Fig. 42-1

15. General View
Gross features of the cerebellum, including the nuclei,
cerebellar peduncles, lobes, folia, and fissures.
(Adapted from Nieuwenhuys et al. 1988)
A. Dorsal view. Part of the right hemisphere has been
cut out to show the underlying cerebellar peduncles.
B. Ventral view of the cerebellum detached from the
brain stem.
C. Midsagittal section through the brain stem and
cerebellum, showing the branching structures of the
cerebellum.

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

17. Motor Hierarchy
1° Som sensory
Intent
Actual
Exerts influence
at all levels

18. Cerebellar divisions
Spinocerebellum:
Vermis
Intermediate hem.
Cerebrocerebellum:
Lateral hem.
Spinocerebellum
(Vermis + Intermed. Hem)
Control of limbs
and trunk
Cerebrocerebellum
(Lateral hemisphere)
Planning of movement+
Vestibulo-cerebellum
(Floculo-nodular lobe)
IVth vent
Vermis
Intermediate hem.
Lateral hem.
Control of eye &
head movements
Balance
NTA Fig. 13-1
Floculo-nodular lobe

19. Inputs and Outputs of Cerebellum

20. The Cerebellum Has Three Functionally Distinct Regions

21. Cerebellar Cortex
Inputs
Climbing fibers
•from Inferior olive
Mossy fibers
Output
Purkinje neurons
Interneurons
Granule neurons
Stellate neurons
Basket neurons
Molecular
Purkinje
Granular
NTA Fig. 13-11
Golgi neurons

22. The Cerebellum Has Three Functionally Distinct Regions
The three functional regions of the cerebellum have different inputs and outputs.

23. a
d
b
c
Cerebellar
Ataxia
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

24. Cerebellar dysfunction
Dysfunction: damage produces the following:
• Ataxia- a disturbance that alters the direction and
extent of voluntary movements; abnormal gait and
uncoordinated movements
• Dysmetria- altered range of motion (misjudge
distance)
• Intention Tremor-oscillating motion, especially of
head,during movement
• Vestibular signs-nystagmus, held tilt

25. Cerebellar dysfunction
1. Small lesions produce no signs or only transient
symptoms; small deficits are compensated for by
other parts of the brain
2. Lesions of the cerebellar hemispheres result in
loss of muscular coordination and jerky puppet-like
movements of the limbs on the ipsilateral side
(same side as lesion)
3. Lesions of the vermis result in truncal tremor
and gait ataxia (splayed stance and swaying of
the body while walking)[

26. References