Proposed mechanisms for cerebellar coordination, stabilization and monitoring of movements and posture.

In this paper cerebellar mechanisms have been proposed for the coordination of all movements, for the learning effect of training on movements, for the effect of mental set on posture and voluntary movements, for the detection of velocity and acceleration, and for the stabilization of movements and posture. Coordination of agonist, antagonist, fixation and synergistic muscles during a movement could occur via a cerebellar matrix which connects agonist efferent feedback from the Motor Cortex to the appropriate antagonist motor cortical neurons. Improved efficiency through repetition (learning) occurs through suggested changes at the molecular and synaptic levels. The Inferior O-live-Climbing Fibre System is seen as a dynamic oscillator; indicating when a movement begins, its velocity and acceleration, and its stability. According to this view, the cerebellum stabilizes movements, and adds the effect of mental set on posture and voluntary movements, by inducing changes in the gain of stretch reflexes. Inhibitory interneurons add versatility to movements, while excitatory collaterals from cerebellar afferents directly to cerebellar deep nuclei improve sensitivity of the system. These mechanisms work for all movements whether active, passive, or reflexive.