11. Purkinje cells:
• Purkinje cells:
– 50 to 100 AP per second
• Deep nuclear cells at much higher rates
• Direct stimulation of deep nuclear cells –Excites
them
• Signals from Purkinje inhibits them
12.
13.
14.
15.
16. Vestibulocerebellum
• Importance in maintaining balance
• Performance of rapid movements
– Change in direction
– Balance b/w agonist and antagonist muscles
• Problem is of time
– Most rapid conduction = 120 m/s --- 10 -15 millisec
– 10 inches movement occurred…………
– IMPOSSIBLE –RETURNING SIGNALS REACH AT
TIME OF MOVEMENT
– Signals from periphery –
• Tell brain the rate and direction of movement
17. • Vestibulocerebellum Calculate In Advance
• INFORMATION FROM PERIPHERY AND VESTIBULAR
APPARATUS
• For anticipatory correction of postural motor signals
– Necessary for maintaining equilibrium
• Peripheral body parts feedback through Vermis
– Vestibulocerebellum help brain stem
• Vestibular nuclei
• Reticular nuclei
– Compute required position of respective parts of
body
20. Spinocerebellum
• Provide smooth coordinate movements of
agonist and antagonist muscles for
– Acute purposeful patterned movements
• Cerebellum compares
Intentions of cerebral cortex
With
Performance of respective parts of body
25. Prevent overshoot and Damp movements
• Because of momentum
– All body movements are pendular
– All movements have tendency to overshoot
• Appropriate learned subconscious signals from
intact cerebellum stop movement precisely at
intended point
• Provide damping
• Prevent tremors and overshoot
26.
27. Cerebellar control of Ballistic movements
• Typing movements Ballistic movements
• Scanning with eyes Saccadic movements
• If cerebellum removed:
– Movements slow to develop
– Force development is weak
– Movements are slow to turn off
Because there is
– No first excitatory and then delayed inhibitory signal
by cerebellum……
28.
29. Cerebro cerebellum
• Lateral zone highly developed and enlarged
• Movements of hand & fingers and speech
performed
• No
– Direct information from periphery of body
– Direct contact with primary motor cortex
• But with premotor and association areas
• If destroyed
– In-coordinate hand/finger movements?
– Speech is in-coordinate?
30.
31. Cerebro cerebellum
• Planning of sequential movements
• Timing of sequential movements
• Extra motor predictive function
• MOTOR LEARNING & COGNITIVE
ROLE
32. Planning of sequential movements
• Planning of sequential movement - Dentate
Nuclei
• Start in sensory and premotor areas of cortex
• Transmitted to lateral zones of cerebellum
• Appropriate motor signals provide
transition from one movement to other
• Involved in PLAN of future movement
33. Timing of sequential movements
• Provide appropriate timing for each movement
• Person recognize the need
• Predict ahead of time, how far different parts of
body will move in given time
• Smooth progression of movement
• If damaged :
• Writing, Running, Speech uncoordinated
34. Extra motor predictive function
• Rates of progression of visual and
auditory phenomenon
– Predicted by brain
– Need Cerebellum
• If large lateral portions of cerebellum of
monkey removed?
