6. Structure
It consists of 2 cerebellar hemispheres connected by
median vermis.
Each cerebellar hemisphere is further divided into an
intermediate zone and a lateral zone.
a. Central zone (Vermis) – Influences the movements of
long axis of the body (neck, shoulders, thorax,
abdomen, hips).
b. Intermediate zone – Influences distal muscles of upper
and lower limbs especially hands & feet.
c. Lateral zone – Planning of movements and correction of
movement errors.
7.
8. Functional Areas of Cerebellum
On the basis of incoming and outgoing
connections with specific areas of nervous
system, cerebellum is divided into 3 areas:
a.Vestibulocerebellum – Flocculonodular
lobe.
b.Spinocerebellum – Vermis, intermediate
zone.
c.Cerebrocerebellum – Lateral zone.
12. Deep Cerebellar Nuclei
Located deep to the layers of cerebellar cortex,
there are 4 masses of gray matter called deep
cerebellar nuclei. They include:
a.Dentate.
b.Emboliform.
c.Globose.
d.Fastigial.
Axons of these deep cerebellar nuclei form the
cerebellar output.
13.
14. Input to Cerebellar Cortex
Climbing Fibers – From inferior olivary nucleus of
medulla oblongata.
Mossy Fibers:
a.From cerebral cortex.
b.From spinal cord – Anterior & posterior
spinocerebellar pathways.
c.From vestibular system.
d.From nucleus cuneatus of medulla oblongata.
e.From red nucleus of midbrain.
18. Functions of Cerebellum
Spinocerebellum:
a.Coordination of movements of agonist and
antagonist muscles of distal limbs during voluntary
purposeful movements.
b.Damping of the movements to prevent
overshooting.
c.Coordination of rapid alternating movements
(ballistic movements) such as saccadic
movements of the eyes during reading.
23. Connections of Basal Ganglia
Basal ganglia are connected via complex circuitry to:
a.Motor cortex.
b.Somatosensory cortex.
c.Ventrolateral (VL) & ventral anterior (VA) nuclei of
Thalamus.
d.Subthalamus.
e.Substantia nigra (midbrain).
f. Red nucleus (midbrain).
g.Reticular formation.
24.
25. Function
a.Control complex patterns of motor activity
e.g., writing of alphabets.
b.Cognitive control of motor activities.
c.Timing of movements.
d.Scaling the intensity of movements.
27. Primary Motor Area
Located in frontal lobe.
Responsible for execution of movements.
Different muscle groups of the body are
represented in different areas of primary motor
area forming a map called motor homunculus.
More than half of entire primary cortex is
concerned with controlling muscles of hands
and speech.
28.
29. Premotor Area
Located in frontal lobe.
Responsible for generating a plan of
movement which is then transferred to
primary motor cortex for execution.
30. Supplementary Motor Area
Located in frontal lobe.
Exact function is not understood.
Lesion of this area does not cause any
paralysis.
31. Pyramidal Tracts
Motor signals are transmitted from motor
cortex to lower motor neurons by means
of:
a. Corticospinal tract → LMNs in anterior
horn of spinal cord.
b. Corticobulbar (cortcionuclear) tract →
LMNs in motor nuclei of cranial nerves
within brainstem.
