The document describes the anatomy and functions of the cerebellum and basal ganglia. The cerebellum is divided into lobes and zones that control muscle movements. It coordinates voluntary movements, controls posture and balance, and performs error correction during movements. The basal ganglia are involved in complex motor patterns, cognitive motor control, regulating movement timing and intensity, inhibiting muscle tone, and axial/limb positioning. Parkinson's disease results from degeneration of basal ganglia neurons and causes rigidity, tremors, slowed movement, and mask-like facial expressions.

1. CEREBELLUM
Dr. SHAROJ KHAN

2. FUNCTIONAL ANATOMY
 Anatomically Cerebellum is
divided into 3 lobes by two
deep fissures:
 Ant. Lobe
 Post. Lobe
 Flocculo-nodular lobe

3. FUNCTIONAL DIVISIONS
 Functionally the
cerebellum is not
organized according to
lobes, but along the
longitudinal axis, into 3
zones:
 Vermis- in the centre
 Intermediate zone
 Lateral zone

4.  Vermis- control for the functions for the
muscles of various parts are located such
as:
 Axial body
 Neck
 Shoulders and hips

5.  Intermediate Zone: Lies on each side of vermis and
is concerned with muscle control in distal portion of
upper & lower limbs, especially
 Hands & Fingers
 Feet and toes

6.  Lateral Zone:
 This area joins with the cerebral cortex in the overall
planning of sequential movements.
 It thus play important role in the timing and sequence of
discrete (different) motor activities which is extremely
important for coordination of motor activities.

7. FUNCTIONS OF CEREBELLUM
 1. Co-ordination of voluntary motor activities:
 Floculo-nodular lobes coordinate most of body’s
equilibrium movements.
 Vermis and Intermediate zones on the two sides
coordinate the movements of the distal portions of the
limbs, especially the hands and fingers.
 Lateral zones: Have both afferent & efferent
connnections with cerebral cortex . Through this
planning of sequential body & limb movements occurs

8.  2. Control of postural & equilibrium Movements.
 3. Error Control- Role of Intermediate zone:
 When a movement is performed the intermediate zone
of cerebellum receives two types of informations:
 Direct from motor cortex and red nuclei:- Intended plan
of movement for the next few fractions of a second.
 Feedback information: from the peripheral parts of body
telling about the actual movements in progress, in distal
parts of limbs.

10.  4. Damping of movements:
 Movements of body tend to be pendular. When a part of
body is moved, momentum develops.
 Because of momentum the movements have a
tendency to overshoot.
 However subconcious signals from cerebellum precisely
at the intended point, thereby preventing the overshoot.
 Damping is caused by the inhibition of deep nuclei by
purkinje cell by the release of GABA.
 Intermediate zone of cerebellum and nucleus play role
in damping

11.  Control of Ballistic Movements by Intermediate
zone:
 For e.g. During typing a movement is already over
before the feedback information could reach the control
system. Thus there is no time for error control.
 So the entire movement is to be preplanned i.e
 When the movement should start?
 How much distance should it go far?
 When should it stop?
 Preplanning is done by cerebellum

12.  6. Motor predictive functionM
 Cerebellum constantly monitors the status of motor
activity and can predict as to when a moving part will
reach which point or how much distance can be covered
by a moving part in a given time.

13. BASAL GANGLIA

14.  Basal ganglia constitute an accessory Motor
system which functions not by itself but in close
association with cerebral motor cortex and cortico
spinal motor system

15.  Main components are:
 Caudate nucleus
 Putamen
 Globus pallidus
 Substantia nigra
 Sub thalamic nuclei

17.  All motor and sensory fibers connecting with
cerebral cortex and spinal cord pass between the
caudate nuclei and putamen. These fibers are
collectively called INTERNAL CAPSULE.

18. NEUROTRANSMITTERS IN BASAL GANGLIA
SYSTEM
 DOPAMINE PATHWAYS: Extend from Subs. Nigra
to caudate nucleus & Putamen
 GABA pathways: From Caudate nucleus &
Putamen to globus pallidus & Substantia nigra
 Acetylcholine pathways: Extend from cerebral
cortex to caudate nucleus and putamen.
 Glutamate pathways ( Multiple): These provide
excitatory signals that balance the inhibitory signals
transmitted by Dopamine & GABA
 General pathways from brainstem secrete
Norepinephrine, serotonin & Enkephalin.

19. FUNCTIONS OF BASAL GANGLIA
 1. Control of complex patterns of motor activity
 Putamen circuit plays impt. Role in these functions
 Such as:
 Writing of letters
 Shooting of basketball
 Passing of football
 Throwing of cricket ball

20.  2. Cognitive control of sequential and parallel motor
patterns- to achieve specific conscious goals.
 Most of motor activities occur as a consequence of
thoughts generated in the mind. This process is called
cognitive control. Caudate nucleus plays major role in
this function as it receives inputs from the association
areas of cerebral cortex that integrate the sensory and
motor info. And translate them into Thought patterns.

21.  Association areas of cortex integrate sensory and
motor information
 Translate them into thought patterns
 Caudate nucleus( Basal ganglia)
 Send efferents
 Directly to UMN
 Indirectly to LMN

22.  3. Change the timing and scale the intensity of
movements:
 E.g. How rapidly the movement is to be performed
 How large the movement has to be performed.
 Timing and scaling is the function of Caudate
nucleus.

23.  4. General Inhibitors of muscle tone:
 B.G are general inhibitors of muscle tone and motor
activity
 GABA and Dopamine function as inhibitory agents and
thus act as a stabilizer and provide stability to the motor
control system.

24.  5. Role of globus pallidus
 Plays role in Axial and girdle movements
 Back ground positioning of body and limbs.

25. LESIONS OF BASAL GANGLIA
 CHOREA
 ATHETOSIS
 HEMIBALLISMUS
 PARKINSON’S DISEASE

26. PARKINSON’S DISEASE
 Condition results due to widespread destruction of
dopaminergic neurones of substantia nigra.
Normally these neurones secrete dopamine in the
caudate nucleus and putamen
 Features
 i. Hyperkinesia
 Rigidity – Lead pipe type
 Tremor- Involuntary tremmors ( rhythmic oscilatory
movements) occur at the rate of 3-6 cycles/sec. For e.g
 Pill rolling movements
 Tremmors of head some times

27.  ii. Akinesia: Difficulty in initiating movements due to
rigidity.
 Iii. Loss of automatic associated movements, such as
 Such as swinging of arms while walking
 Changes in facial expressions with changes in emotional
feelings
 Subconciously occuring movements during standing
 As a result of loss of movements of expression the face
becomes expressionless- Mask like face.
 Iv. Festinant Gait : person walks with short and quick
steps with the body bent forwards