Gross Appearance Structure Functional areas Intracerebellar nuclei Cerebellar afferent fibers Cerebellar efferent fibers

1. The CerebellumThe Cerebellum
and itsand its
ConnectionsConnections
Dr. Shittu LAJDr. Shittu LAJ

2. Learning outlinesLearning outlines
 Gross AppearanceGross Appearance
 StructureStructure
 Functional areasFunctional areas
 Intracerebellar nucleiIntracerebellar nuclei
 Cerebellar afferent fibersCerebellar afferent fibers
 Cerebellar efferent fibersCerebellar efferent fibers

3. Gross featuresGross features
 The cerebellumThe cerebellum
or ‘small brain’ isor ‘small brain’ is
the largest partthe largest part
of the hind brainof the hind brain
 It lies posterior toIt lies posterior to
the fourththe fourth
ventricle, theventricle, the
pons and thepons and the
medullamedulla
oblongataoblongata

4. cerebellumcerebellum
 The cerebellum is located in the posteriorThe cerebellum is located in the posterior
cranial fossa,cranial fossa,
 separated from the occipital lobes ofseparated from the occipital lobes of
cerebrum by a dural fold, thecerebrum by a dural fold, the tentoriumtentorium
cerebellicerebelli
 The cerebellum is connected to the midbrain,The cerebellum is connected to the midbrain,
pons and medulla oblongata bypons and medulla oblongata by three pairsthree pairs
of peduncles-of peduncles-
 SCPSCP
 MCPMCP
 ICPICP

5. Gross features

6. Gross features

7. Lateral view of theLateral view of the
brainbrain

8. Lobes andLobes and
SubdivisionsSubdivisionsAA AnatomicAnatomic
subdivisionssubdivisions
Transverse planeTransverse plane
LongitudinalLongitudinal
planeplane
AnteriorAnterior
lobelobe
VermisVermis
PosteriorPosterior
lobelobe
ParavermisParavermis
FlocculonodularFlocculonodular
lobelobe
HemisphereHemisphere
BB FunctionalFunctional
subdivisionssubdivisions SpinocerebelSpinocerebel
lumlum
CerebrocerebCerebrocereb
ellumellum
VestibulocerebelluVestibulocerebellu
mm
CC PhylogeneticPhylogenetic
subdivisionssubdivisions
PaleocerebelPaleocerebel
lumlum
NeocerebelluNeocerebellu
mm
ArchicerebellumArchicerebellum 8

9. Anatomic subdivisionsAnatomic subdivisions
Transverse plane

10. Longitudinal Plane: -
Midline (Vermis)
- Intermediate
(Paravermal)
- Lateral (Hemisphere)
Anatomic subdivisions

12. Functional subdivisionsFunctional subdivisions
 1) The vestibulocerebellum:1) The vestibulocerebellum:
 Corresponds with theCorresponds with the
flocculonodular lobeflocculonodular lobe
 Reciprocal connections withReciprocal connections with
vestibular and reticular nucleivestibular and reticular nuclei
 Plays a role in control of bodyPlays a role in control of body
equilibrium and eye movementequilibrium and eye movement

14. The spinocerebellum:The spinocerebellum:
 Corresponds to theCorresponds to the anterioranterior
lobelobe
 Reciprocal connections withReciprocal connections with
the spinal cordthe spinal cord
 Plays a role in control ofPlays a role in control of
muscle tonemuscle tone

16. The cerebrocerebellum:The cerebrocerebellum:
 Corresponds to theCorresponds to the posteriorposterior
lobelobe
 Reciprocal connections with theReciprocal connections with the
cerebral cortexcerebral cortex
 Plays a role in planning andPlays a role in planning and
initiation of movementsinitiation of movements

18. Phylogenetic subdivisionsPhylogenetic subdivisions
 The archicerebellumThe archicerebellum – oldest zone,– oldest zone,
corresponds with thecorresponds with the flocculonodularflocculonodular
lobelobe
 The paleocerebellumThe paleocerebellum – more recent than– more recent than
archicerebellum, corresponds to thearchicerebellum, corresponds to the
anterioranterior lobelobe
 The neocerebellumThe neocerebellum – most recent– most recent
phylogenetically, corresponds to thephylogenetically, corresponds to the

19. Functional areasFunctional areas
19

20.  TheThe posterior lobeposterior lobe contains on its inferior surface, thecontains on its inferior surface, the
cerebellar tonsilscerebellar tonsils
 In cases ofIn cases of ↑↑intracranial pressure, the cerebellar tonsils mayintracranial pressure, the cerebellar tonsils may
herniate through the foramen magnumherniate through the foramen magnum
 ThisThis tonsilar herniationtonsilar herniation is ais a life-threatening neurologiclife-threatening neurologic
emergencyemergency due to compromise of vital centers in the braindue to compromise of vital centers in the brain
stemstem
20

21. Structure-anatomicStructure-anatomic
 The cerebellum is composed of:The cerebellum is composed of:
 Gray matterGray matter – outer covering, called cortex– outer covering, called cortex
 Gray matter of the cortex has a uniformGray matter of the cortex has a uniform
structure and divided into three layers –structure and divided into three layers –
molecular layer, Purkinje cell layer andmolecular layer, Purkinje cell layer and
granular layergranular layer
 White matterWhite matter – inner layer. White matter of– inner layer. White matter of
each hemisphere contains three masses ofeach hemisphere contains three masses of
gray matter, called thegray matter, called the intracerebellar nucleiintracerebellar nuclei

22. StructureStructure

23. StructureStructure
 White matterWhite matter
 There is small amount of white matter in theThere is small amount of white matter in the
vermis and it closely resembles the trunk andvermis and it closely resembles the trunk and
branches of a tree –branches of a tree – the arbor vitaethe arbor vitae
 The white matter is made up of three groupsThe white matter is made up of three groups
of fibers: (1)of fibers: (1) intrinsic, (2) afferent, and (3)intrinsic, (2) afferent, and (3)
efferentefferent
 The intrinsic fibersThe intrinsic fibers do not leave thedo not leave the
cerebellum but connect different regions of thecerebellum but connect different regions of the
organorgan

24. The intracerebellar nucleiThe intracerebellar nuclei
A commonly
used
mnemonic to
recall the
deep
cerebeller
nuclei from
“lateral to
medial” is:
“Don’t Eat
Greasy Food”

25. Functional areasFunctional areas

26. Cerebellar afferent fibersCerebellar afferent fibers
 The afferent fibers form the greater partThe afferent fibers form the greater part
of the white matterof the white matter
 They enter the cerebellum mainly throughThey enter the cerebellum mainly through
the inferior and middle cerebellarthe inferior and middle cerebellar
pedunclespeduncles
Afferent fibers from cerebral cortex:Afferent fibers from cerebral cortex:
1.1. Corticopontocerebellar pathwayCorticopontocerebellar pathway
2.2. Cerebro-olivocerebellar pathwayCerebro-olivocerebellar pathway
3.3. Cerebroreticulocerebellar pathwayCerebroreticulocerebellar pathway

27. Cerebellar afferent fibersCerebellar afferent fibers
 Afferent fibers from spinal cord:Afferent fibers from spinal cord:
1.1. Anterior spinocerebellar tractAnterior spinocerebellar tract
2.2. Posterior spinocerebellar tractPosterior spinocerebellar tract
3.3. Cuneocerebellar tractCuneocerebellar tract
 Afferent fibers from the vestibular nerveAfferent fibers from the vestibular nerve
1.1. Vestibulocerebellar tractVestibulocerebellar tract

28. Cerebellar efferent fibersCerebellar efferent fibers
 The entire output of the cerebellar cortex is throughThe entire output of the cerebellar cortex is through
the axons of the Purkinje cellsthe axons of the Purkinje cells
 The efferent fibers from theThe efferent fibers from the cerebellumcerebellum connect withconnect with
thethe red nucleus, thalamus, vestibular complex, andred nucleus, thalamus, vestibular complex, and
reticular formationreticular formation
 The efferent pathways are:The efferent pathways are:
1.1. Globose-Emboliform-Rubral PathwayGlobose-Emboliform-Rubral Pathway
2.2. Dentothalamic PathwayDentothalamic Pathway
3.3. Fastigial Vestibular PathwayFastigial Vestibular Pathway
4.4. Fastigial Reticular PathwayFastigial Reticular Pathway
Through superior
cerebellar peduncle
Through inferior cerebellar
peduncle

29. KEY CONCEPTSKEY CONCEPTS
 The major inputs to the cerebellum are from threeThe major inputs to the cerebellum are from three
sources: spinal cord, vestibular system, andsources: spinal cord, vestibular system, and
cerebral cortexcerebral cortex
 Deep cerebellar nuclei provide cerebellar output toDeep cerebellar nuclei provide cerebellar output to
extracerebellar targetsextracerebellar targets
 Extracerebellar targets include the vestibular andExtracerebellar targets include the vestibular and
reticular nuclei, red nucleus, and thalamusreticular nuclei, red nucleus, and thalamus

30. Key conceptsKey concepts
 Signs of cerebellar disorders include asynergia, dysarthria,Signs of cerebellar disorders include asynergia, dysarthria,
adiadochokinesis, dysmetria, tremor, muscular hypotonia,adiadochokinesis, dysmetria, tremor, muscular hypotonia,
ataxia and nystagmusataxia and nystagmus
 Signs of cerebellar disease are ipsilateral to the side ofSigns of cerebellar disease are ipsilateral to the side of
cerebellar lesioncerebellar lesion
 Lesions of the vermis are manifest by abnormalities inLesions of the vermis are manifest by abnormalities in
trunk movementtrunk movement
 Lesions of cerebellar hemispheres are manifested byLesions of cerebellar hemispheres are manifested by
abnormalities of movement in the extremitiesabnormalities of movement in the extremities