Mechanism of Action of Corticocerebellum

Mechanism of Action of Corticocerebellum

1. Damping action

Damping action refers to prevention of exaggerated muscular activity. This helps in making the voluntary

movements smooth and accurate. All the voluntary muscular activities are initiated by motor areas of cerebral cortex. Simultaneously, corticocerebellum receives impulses from motor cortex as well as feedback signals from the muscles, as soon as the muscular activity starts. Corticocerebellum, in turn, sends information (impulses) to cerebral cortex to discharge only appropriate signals to the muscles and to cut off any extra impulses. Because of this damping action of corticocerebellum, the exaggeration of muscular activity is prevented and the movements become smooth and accurate. Literally, the word damping means any effect that decreases the amplitude of mechanical oscillation.

2. Control of ballistic movements

Ballistic movements are the rapid alternate movements, which take place in different parts of the body

while doing any skilled or trained work like typing, cycling, dancing, etc. Corticocerebellum plays an

important role in preplanning the ballistic movements during learning process.

3. Timing and programming the movements

Corticocerebellum plays an important role in timing and programming the movements, particularly during learning process. While using a typewriter or while doing any other fast-skilled work, a chain of movements occur rapidly in a sequential manner. During the learning process of these skilled works, corticocerebellum plans the various sequential movements. It also plans schedule of time duration of each movement and the time interval between movements. All the information from corticocerebellum

are communicated to sensory motor area of cerebral cortex and stored in the form of memory. So, after the learning process is over, these activities are executed easily and smoothly in a sequential manner.

4. Servomechanism

Servomechanism is the correction of any disturbance or interference while performing skilled work. Once the skilled works are learnt, the sequential movements are executed without any interruption. Cerebellum lets the cerebral cortex to discharge the signals, which are already programed and stored at sensory motor cortex and does not interfere much. However, if there is any disturbance or interference, the corticocerebellum immediately influences the cortex and corrects the movements.

5. Comparator function

Comparator function of the corticocerebellum is responsible for the integration and coordination of the

various muscular activities. On one side, cerebellum receives the information from cerebral cortex, regarding the cortical impulses which are sent to the muscles. On the other side, it receives the feedback information (proprioceptive impulses) from muscles, regarding their actions under the instruction of cerebral cortex. By receiving the messages from both ends, corticocerebellum compares the cortical commands for muscular activity and the actual movements carried out by the muscles. If any correction is to be done, then, corticocerebellum sends instructions (impulses) to the motor cortex.

Accordingly, cerebral cortex corrects or modifies the signals to muscles, so that the movements become accurate, precise and smooth. This function of corticocerebellum is known as comparator function.

Simultaneously, it also receives impulses from tactile receptors, eye and ear. Such additional information

facilitates the comparator function of corticocerebellum.

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