1) The cerebellum receives sensory information from the spinal cord, brainstem, and cerebral cortex, and coordinates movement through its output to motor areas. It acts as a feedback loop to smooth and refine motor commands. 2) Lesions of the cerebellum cause ataxia, tremors, balance and posture problems, and difficulties with motor learning and coordination. 3) Purkinje neurons in the cerebellar cortex integrate inputs from mossy fibers and climbing fibers and inhibit targets in the deep cerebellar nuclei through GABA signaling.

1. THE CEREBELLUM

2. OUTLINE
INTRODUCTION ORGANIZATION
AND SUBDIVISONS
CEREBELLAR
PEDUNCLES
AFFERENTAND
EFFERENT
CONNECTIONS
CEREBELLAR
CIRCUIT
FUNCTIONS LESIONSAND
CONSEQUENCES

3. INTRODUCTION
LOCATION
CEREBELLUM

5. A) LAMINATED CEREBELLAR CORTEX
B) DEEP CEREBELLAR NUCLEI

7. CEREBELLAR PEDUNCLES
connect the cerebellum to the brain
stem.[1]
1) Superior cerebellar peduncle
(brachium conjunctiva)
Connects cerebellum to mid-brain.
2) Middle cerebellar peduncles
(Brachium pontis)
Connects cerebellum to the pons
3) Inferior cerebellar peduncle
(Restiform body )
Connects with medulla oblongata.

8. MOTOR SYSTEM IS ORGANIZED
AS HIERARCHY
The Cerebellum Functions As a
Rapid Corrective Feedback Loop,
Smoothing And
Coordinating Movements.
Cerebellum Receives Information From
a)Somato Sensory
b)Visual
c)Auditory
d)Vestibular
e)Proprioceptive

9. COMPONENTS OF BRAINSTEM AND DIENCEPHALON RELATED TO CEREBELLUM

10. INPUT TO CEREBELLUM

11. Temporal and occipital cortices provide the
cerebellar cortex with signals associated with auditory and
visual functions. Somatosensory signals also reach the
cerebellar cortex from the cerebral cortex.
The disynaptic pathway from the cerebral cortex to the
cerebellar cortex with a synapse in the deep pontine
nuclei.
Corticopontine fibers are shown in red, and
pontocerebellar fibers are shown in blue.
INPUTS FROM CEREBRUM

12. INPUT FROM
BRAINSTEM
• These include pathways arising
from
• The Red Nucleus (shown In
Blue),
• Deep Pontine Nuclei (shown In
Red ),
• Vestibular Nuclei, and Reticular
Formation.
• In humans, The Inferior
Olivary Nucleus appears to
transmit an integrated signal
from the spinal cord and
cerebral cortex to the
cerebellar hemispheres via the
climbing fiber system.

13. The pathways most critical for supplying
such inputs to the cerebellum include
A)The dorsal spinocerebellar tract,
B)Ventral spinocerebellar tract,
C)Cuneocerebellar tract, and
D)The rostral spinocerebellar tract (the
latter identified in the cat).
Fibers from the spinal cord
convey information from cutaneous
afferents , joint afferents, and muscle
spindles to the inferior olivary nucleus.
From this structure, axons pass to the
contralateral cerebellar cortex via the
inferior cere-bellar peduncle, terminating
somatotopically within the anterior and
posterior lobes of the cerebellar cortex
Therefore, these receiving areas are
referred to as the spinocerebellum
INPUT FROM
SPINAL CORD

16. ASCENDING OUTPUT FROM CEREBELLUM

17. DESCENDING OUTPUT FROM CEREBELLUM

18. OVERVIEW
INPUT AND
OUTPUT OF
CEREBELLUM

19. CEREBELLAR CORTEX
microscopically composed of three cell layers
1)The innermost layer is called the granular
cell layer.
2)The middle layer is the Purkinje cell layer,
3)The most superficial layer is called the
molecular layer, which is almost devoid of
cells.
Five types of neurons
1)Basket cells and 2)stellate cells
( Molecular cell layer) GABA
3)Purkinje cells (Purkinje cell layer)GABA
4)Granule cell( GLUTAMATE) and
5)Golgi cell
(Granular cell layer)GABA
CEREBELLAR CORTICAL NEURONS

20. CEREBELLAR CIRCUIT

21. INPUT TO CEREBELLAR CIRCUIT

22. OUTPUT TO CEREBELLAR CIRCUIT

24. INPUT AND OUTPUT OF CEREBELLAR CORTEX
• EXCITATORY LOOP
• INHIBITORY LOOP

25. HOW DOES PURKINJE
NEURON FIRING
AFFECT MOVEMENT ?
Purkinje neurons are inhibitory thus
when they slow or stop firing their
targets are excited.

26. Purkinje Cells Show Two Firing
Patterns:
A)Complex Spikes Occur In Response
To Climbing fiber Excitation.
B)Simple Spikes Are Typical Action
Potentials

27. COMPLEX SPIKES INDICATE
ERRORS
RATE OF COMPLEX SPIKES ~50 S
RATE OF SIMPLE SPIKES ~1- 2 S
Rate Of Complex Spikes Increases With Errors
In A Novel Task.
Rate Of Complex Spikes Decreases After
Learning Correct Errors In Performance .
Climbing fibers Thus Function As ”
Teachers” And Adaptively Shape Cerebellar
Output.

31. FUNCTIONS OF CEREBELLUM

32. CEREBELLAR DYSFUNCTION
CEREBELLUM IS A FAST FEEDBACK LOOP FOR
COORDINATING ,MOVEMENT CEREBELLAR LESIONS.
CHARACTERISTICS FEATURE
A)DISTURBANCE OF POSTURE
HYPOTONIA
FACE ROTATED TOWARDS OPPOSITE SIDE
BODY WEIGHT THROWN ON HEALTHY LEG,CONCAVITY OF TRUNK
TOWARDS AFFECTED SIDE
NYSTAGMUS
B) INTENTION TREMORS
JERKY MOVEMENTS WITH TO AND FRO MOTION ON REACHING
AN OBJECT
COARSE TREMOR OCCURING AT4- 6/SECD

33. C)ATAXIA
INCOORDINATION OF MOVEMENTS
MOVEMENTS DECOMPOSED INTO JERKY AND IMPRECISE ACTIONS.
DYSMETRIA MOVEMENT IS POORLY CARRIED OUT IN DIRECTION,RANGE
AND FORCE PAST
POINTING HYPERMETRIA FALLING SHORT HYPOMETRIA
D)SLOW AND LALLING SPEECH
E)DRUNKEN GAIT
F)DYSDIADOKINESIA
ALSO DEFICITS IN MOTOR LEARNING.
CONT….

34. SUMMARY
1) The cerebellum balances motor commands and sensory information to smooth and coordinate movement.
2)Lesions of cerebellum cause ataxia,tremor,balance and posture problems.
3)Inputs to cerebellum mossy fibers (pons and spinal cord) and climbing fibers( inferior olive)
The inputs from the spinal cord provide the cerebellum with essential information (i.e., The status and position
of individual as well as groups of muscles) with which it can control both muscle tone and the execution of
movements.
4)Purkinje neurons use the neuro transmitter GABA and inhibit their targets in the deep nuclei.
Output from cerebellum deep nuclei to red nucleus, thalamus, inferior olive and vestibular nuclei.
5)Associative forms of motor learning occur in the cerebellum.

35. THANKYOU