The saccadic eye movement-related potentials (SEMRPs) were recorded over various brain areas in a group of righthanders while they performed saccades to visual stimuli appearing either at regular or at irregular time intervals. The premotion positivity, motion execution component and lambda responses were of shorter latencies and lower amplitudes over the parietal areas as compared to the occipital ones. This finding did not depend on the regularity of intervals. With regular intervals, the positive wave starting before and peaking at the end of a saccade was found over the frontal eye fields. With irregular intervals, the premotion negativity was registered over the motor and frontal cortices. With saccades at regular intervals, the oculomotor components in the SEMRPs were less pronounced as compared to the irregular ones. These results are in accordance with the presumption that visual stimuli, appearing at irregular intervals, require higher attention and readiness to the oculomotor reaction, respectively, and also with the supposed role of the right hemisphere of righthanders in processing visual information.
It is accepted that the formulation of the motor program in the
brain is not only the perceptual and motor function but also the
cognitive one. Therefore it is not surprising that the execution of saccadic eye movements can by substantially affected be the on-going mental activity of a given person. Not only the distribution of attention, but also the focusing the attention may influence the main gain of saccades, their accuracy. Patients suffering from mental disorders have strongly engaged their attention focused at their mental processes. The nature of their problems may be linked to perceptual and/or analytical processing. Such so-called mental set may significantly affect their oculomotor activity in the course of their saccadic eye movement examinations. This short comment points out not only to the influence of the contextually guided and generated saccadic eye movements upon their
accuracy but also to the distribution and focusing the attention. The effect of the functional brain asymmetry upon the visually generated saccades and the possible effect of biologically active substances upon the voluntary generated saccades are briefly mentioned. All these influences should be taken into account when planning the saccadic eye movement task. It may be concluded that the repetition of the same oculomotor task in a given person has to be introduced. This may help to follow the effect of complex therapy namely.