The document provides information about the cerebellum including its anatomy, development, functions, and disorders. It describes the cerebellum's role in motor control and coordination. Anatomically, it discusses the cerebellum's lobes, zones, layers and internal structures. It also outlines the cerebellum's input pathways from various sensory systems and its output pathways to motor control centers. Regarding development, it notes the cerebellum arises from the rhombic lip and progresses through four histogenesis stages. Finally, it lists some common cerebellar disorders like ataxias and degenerations.

1. GURUGRAM
UNIVERSITY
M.Sc Neuroscience

2. CEREBELLUM
PRESENTED BY Mr. SACHIN
M. Sc. Neuroscience

3. Objective
• Introduction
• Anatomy
• Histogenesis of Cerebellar Cortex
• Development of the cerebellum
• Blood Supply Of The Cerebellum
• Cerebellum function
• Cerebellum Disorders

4. Introduction
• The cerebellum, which stands for “little brain”, is a structure of the
central nervous system.
• It has an important role in motor control, with cerebellar
dysfunction often presenting with motor signs.
• It is active in the coordination, precision and timing of
movements, as well as in motor learning.
• The cerebellum is located at the back of the brain, immediately
inferior to the occipital and temporal lobes, and within the
posterior cranial fossa.

6. Cerebellum- Anatomy
• The cerebellum consists of two hemispheres which are connected by the
vermis, a narrow midline area. Like other structures in the central
nervous system, the cerebellum consists of grey matter and white
matter:
• Grey matter – located on the surface of the cerebellum. It is tightly
folded, forming the cerebellar cortex.
• White matter – located underneath the cerebellar cortex. Embedded in
the white matter are the four cerebellar nuclei (the dentate,
emboliform, globose, and fastigi nuclei).
• There are three ways that the cerebellum can be subdivided –
anatomical lobes, zones and functional divisions.

7. Cerebellar- Anatomy
• Anatomical Lobes-
• There are three anatomical lobes that can be
distinguished in the cerebellum; the anterior lobe,
the posterior lobe and the flocculonodular lobe.
• These lobes are divided by two fissures – the
primary fissure and posterolateral fissure

8. Cerebellum- Anatomy
• Zone-
• There are three cerebellar zones.
• In the midline of the cerebellum is the
vermis. Either side of the vermis is the
intermediate zone.
• Lateral to the intermediate zone are the
lateral hemispheres

9. Cerebellum- Anatomy
• Functional Division
• The cerebellum can also be divided by function. There are three
functional areas of the cerebellum – the cerebrocerebellar, the
spinocerebellar and the vestibulocerebellum.
• Cerebrocerebellar – the largest division, formed by the lateral
hemispheres. It is involved in planning movements and motor
learning.
• It receives inputs from the cerebral cortex and pontine nuclei, and
sends outputs to the thalamus and red nucleus.
• This area also regulates coordination of muscle activation and is
important in visually guided movements

10. Cerebellum- Anatomy
Functional Divisions
• Spinocerebellar – comprised of the vermis and
intermediate zone of the cerebellar
hemispheres.
• It is involved in regulating body movements by
allowing for error correction. It also receives
proprioceptive information.
• Vestibulocerebellum – the functional equivalent
to the flocculonodular lobe. It is involved in
controlling balance and ocular reflexes, mainly
fixation on a target.
• It receives inputs from the vestibular system,
and sends outputs back to the vestibular nuclei
and intermediate zones

11. Cerebellum-
Internal Structure
• Cerebellum has a superficial grey mantle called cerebellar cortex.
• Deep to cortex lies the white matter forming central core from which nerve fibers
spread towards the
• cortex in typical branching pattern called arbor vitae.
• White matter consists of afferent and efferent fibers.
Nuclei
• White matter is made up of four pairs of cerebellar nuclei,
1.Fastigial Nucleus- It receives input from the vermis and from cerebellar
afferents that carry vestibular, proximal somatosensory, auditory, and visual
information.
2.Globose Nucleus- They receive input from the intermediate zone and from
cerebellar afferents that carry spinal, proximal somatosensory, auditory, and
visual information.
3.Emboliform Nucleus – they work as globose nucleus.
4.Dentate Nucleus- It receives input from the lateral hemisphere and from
cerebellar afferents that carry information from the cerebral cortex (via the
pontine nuclei).
• All outputs from the cerebellum originate from the cerebellar deep
nuclei. Thus, a lesion to the cerebellar nuclei has the same effect as
a complete lesion of the entire cerebellum. It is important to know
the inputs, outputs, and anatomical relationships between the
different cerebellar nuclei and the subdivisions of the cerebellum

12. INPUT AND OUTPUT OF THE CEREBELLUM
• Cerebellar peduncles- Three fiber bundles carry the input and
output of the cerebellum.
1.The inferior cerebellar peduncle (also called the restiform
body) primarily contains afferent fibers from the medulla, as well as
efferents to the vestibular nuclei.
2.The middle cerebellar peduncle (also called the brachium
pontis) primarily contains afferents from the pontine nuclei.
3.The superior cerebellar peduncle (also called the brachium
conjunctivum) primarily contains efferent fibers from the cerebellar
nuclei, as well as some afferents from the spinocerebellar tract.
• Thus, the inputs to the cerebellum are conveyed primarily through
the inferior and middle cerebellar peduncles, whereas the outputs
are conveyed primarily through the superior cerebellar peduncle.
The inputs arise from the ipsilateral side of the body, and the
outputs also go to the ipsilateral side of the body.

13. Via the caudal cerebellar peduncle the cerebellum receives proprioceptive afferents from
the dorsal spinocerebellar tract and lateral cuneate nucleus. (Some proprioception travels
in a ventral spinocerebellar tract through the rostral cerebellar peduncle.) The cerebellum
receives input from the motor cortex via pontine nuclei and the middle cerebellar peduncle.
The olivary nucleus also receives proprioceptive input from spinal tracts and collateral
branches from descending motor tracts. Then the olivary nucleus sends axons to the
cerebellum through the contralateral caudal cerebellar peduncle. The axons terminate
as climbing fibers.

14. Cerebellar output is from cerebellar nuclei (except for some flocculonodular cortical
projections to vestibular nuclei). The fastigial nucleus sends axons to reticular formation
and vestibular nuclei via the caudal cerebellar peduncle. The interpositus nucleus sends
axons to the red nucleus via the rostral cerebellar peduncle. The dentate nucleus sends
axons (directly & indirectly) to the thalamus via the rostral cerebellar peduncle. The
thalamus projects axons to motor areas of cerebral cortex.

15. Histogenesis of Cerebellar Cortex
• It is the outer covering of the surfaces of the cerebral
hemispheres and is folded into peaks called gyri, and grooves
called sulci.
• The cerebral cortex mostly consists of the six-layered neocortex,
with just 10% consisting of allocortex.
• The neocortex is separable into different regions of cortex
known in the plural as cortices and include the motor cortex
and visual cortex.
• It is separated into two cortices, by the longitudinal fissure that
divides the cerebrum into the left and right cerebral
hemispheres.
• The two hemispheres are joined beneath the cortex by the
corpus callosum.

16. Layers of Neocortex
• Layer I
• Molecular layer, and contains few scattered neurons, including
GABAergic rosehip neurons, Cajal-Retzius cells, dendritic tufts of
pyramidal neurons, stellate cells and horizontally oriented axons,
as well as glial cells.
• Layer II
• It is external granular layer, contains small pyramidal neurons and
numerous stellate neurons.

17. Layers of Neocortex
• Layer IIl
• It is external pyramidal layer, contains predominantly small and
medium-size pyramidal neurons, as well as non-pyramidal neurons.
• Layers I through III are the main target of interhemispheric
corticocortical afferents, and layer III is the
• principal source of corticocortical efferent.
• Layer IV
• It is internal granular layer, contains different types of stellate and
pyramidal cells, and is the main target of thalamocortical afferents
from thalamus type C neurons (core-type ) as well as intra-
hemispheric corticocortical afferents.
• The layers above layer IV are also referred to as supragranular layers
(layers I-III), whereas the layers below are referred to as infragranular
layers (layers V and VI

18. Histogenesis of cerebellum cortex

19. Layers of Neocortex
• Layer V
• It is internal pyramidal layer, contains large pyramidal neurons.
• Axons from these leave the cortex and connect with subcortical structures
including the basal ganglia.
• In the primary motor cortex of the frontal lobe, layer V contains giant pyramidal
cells called Betz cells, whose axons travel through the internal capsule, the brain
stem, and the spinal cord forming the corticospinal tract, which is the main
pathway for voluntary motor control.
• Layer VI
• It is polymorphic or multiform layer, contains few large pyramidal neurons and
many small spindle-like pyramidal and multiform neurons; layer VI sends efferent
fibers to the thalamus, establishing a very precise reciprocal interconnection
between the cortex and the thalamus

20. Development of the cerebellum
• The cerebellum develops from the rhombic lip, the dorsal part of
the alar plate of the metencephalon.
• Two rounded swellings develop which at first project partly into
the ventricle forming the rudimentary cerebellar hemispheres.

21. Four stages in the histogenesis of the
• Purkinje cells and cells of the cerebellar nuclei are produced by the
ventricular epithelium and are in the process of migration to their
future positions.
• The cells of the superficial matrix (the external granular layer) take
their origin from the ventricular epithelium at the caudal pole of the
cerebellar anlage and migrate rostrally over its surface.

22. • After migration the Purkinje cells constitute a multicellular layer
beneath the external granular layer. Cell production in the
ventricular epithelium has stopped. The remaining cells transform
into ependymal cells.

23. • Granule cells are produced by the external granular layer and
migrate inwards through the Purkinje cell layer to their position in
the granular layer. Purkinje cells spread into a monolayer.
• Adult position of cortical and nuclear neurons.

24. Blood Supply Of The Cerebellum
• The cerebellum takes blood supply from three
paired arteries
• Superior cerebellar artery (SCA)
• Anterior inferior cerebellar artery (AICA)
• The SCA and AICA are branches of the basilar
artery
• Posterior inferior cerebellar artery (PICA)
• The PICA is a branch of the vertebral artery
• Venous drainage by the superior and interior
cerebellar veins. They drain toward the
superior petrosal transverse, and straight
dural venous sinuses

25. Cerebellum function
• The cerebellum has several functions Trusted Source relating to
movement and coordination, including:
• Maintaining balance: The cerebellum has special sensors that
detect shifts in balance and movement. It sends signals for the
body to adjust and move.
• Coordinating movement: Most body movements require the
coordination of multiple muscle groups. The cerebellum times
muscle actions so that the body can move smoothly.
• Vision: The cerebellum coordinates eye movements

26. Cerebellum function
• Motor learning: The cerebellum helps the body to learn
movements that require practice and fine-tuning. For example,
the cerebellum plays a role in learning to ride a bicycle or play a
musical instrument.
• Other functions: Researchers believe the cerebellum has some
role in thinking, including processing language and mood.
However, findings on these functions are yet to receive full
exploration

27. Cerebellum Disorders
• There are many disorders of the cerebellum, including:
• Ataxias - failure of muscle control in the arms and legs that
result in Movement disorder
• Degeneration - disorders caused by brain cells decreasing
in size or wasting away.
• Congenital disorders (conditions you have at birth,
such as chari malformation).
• Immune and inflammatory conditions (an example of
this is multiple sclerosis).
• Genetic disorders (conditions you have at birth that
you inherited from one or both parents, such as Wilson
disease).

28. • Vitamin deficiencies and nutrition problems (such as
low vitamin B12 levels).
• Stroke-Stroke is a decrease in, or blockage of, the blood
supply to the brain. Only around 1-4%of strokes occur in the
cerebellum.
• Toxins-The cerebellum is vulnerable to poisons, including
alcohol and certain prescription medications. These poisons
damage nerve cells in the cerebellum, leading to ataxia.
• Infection-these can happen because of bacteria, viruses,
parasites and fungi.

29. THANK YOU FOR YOUR ATTENTION