Attentional processes and motor programs of eye movements.

The eye movements is the final result of many processes of sensory-motor integration. The motor programs of saccades may be modified by behavioral states and by drugs.We found in monkey that attentional processes may change the velocity profiles of saccades. As a matter of fact the spontaneous saccades in the dark or in laboratory light very frequently show a velocity profile with two or more maximum velocities or inflection points. When the animal makes saccdes between targets, and if it does this correctly it will receive a reward (some drops of water), the velocity pprofiles show only one maximum velocity. We defined the profiles irregular, in the former case, and regular in the latter one.Since the wakefulness is constant, a passive attentional stimulus evokes an unrewarded saccde of regular type anfd the irregular saccades are present before and after a trial, our hipothesis is that the different way to program the velocity may be due to attention. Particularly, attentional processes may change the discharge of premotor cells in the brainstem.(Supported by MPI-CNR).