12. Functions of Cerebellum
• Turn-On/Turn-Off and Turn-Off/Turn-On
Output Signals from the Cerebellum
• The Purkinje Cells “Learn” to Correct Motor
Errors—Role of the Climbing Fibers
• Function of the Cerebellum in Overall Motor
Control
13. Function of the Cerebellum in Overall
Motor Control
• Vestibulocerebellum—Its Function in Association with the Brain
Stem and Spinal Cord to Control Equilibrium and Postural
Movements
• Spinocerebellum—
- Feedback Control of Distal Limb Movements by Way of
the Intermediate Cerebellar Cortex and the Interposed Nucleus
- Function of the Cerebellum to Prevent Overshoot of
Movements and to “Damp” Movements.
- Cerebellar Control of Ballistic Movements.
• Cerebrocerebellum—
- Function of the Large Lateral Zone of the Cerebellar
Hemisphere to Plan, Sequence, and Time Complex Movements
- Extramotor Predictive Functions
14. Functions
• Comparator function
• Damping function
• Timing & Programming of movements
- Planning of sequential movements
- Timing function
- Predictive function
• Control of Ballistic movements
• Servomechanism
15. 1) What would happen if an expanding mass (such as a tumor) is
pushing caudally on the cerebellum?
2) What would be the effects of a unilateral cerebellar hemisphere
lesion?
3) What would be the effects of a lesion of the cerebellar vermis (in the
midline of the cerebellum)?
16. 1) What would happen if an expanding mass (such as a tumor) is
pushing caudally on the cerebellum?
If the cerebellum is pushed caudally by an expanding mass, the tonsils may be
jammed into the foramen magnum, thereby compressing the medulla or upper
cervical spinal cord (often fatal).
17. 2) What would be the effects of a unilateral cerebellar
hemisphere lesion?
• As illustrated in the simplified
diagram on the right, the effects
of a unilateral cerebellar
hemisphere lesion (shown with a
red X) would be:
1. ipsilateral limb ataxia and
dysmetria
2. ipsilateral intention tremor
3. ipsilateral dysdiadochokinesia
4. ipsilateral limb hypotonia
18. 3) What would be the effects of a lesion of the cerebellar vermis (in the midline of the
cerebellum)?
The effects of a lesion of the cerebellar vermis would be:
1.Gait ataxia
2.Trunk ataxia
3.Dysarthria
4.Nystagmus and other disturbances of eye movement
Note: A relatively common cause of progressive degeneration
of the cerebellar vermis (producing the effects listed above)
is chronic alcoholism.
