ИСТИНА

To attend relevant stimuli in the visual field while ignoring distracter elements is crucial for successful goal-directed behaviour. The oculomotor system can be used as a model to study the competition between different elements in the visual space. The goal of our research was to analyse spatial-temporal parameters of saccades and presaccadic EEG-potentials at the simultaneous presentation of the target and distracting stimuli to the leading and unleading eye. 14 healthy right-handed volunteers participated in the study. Target and distracting peripheral visual stimuli were presented simultaneous monocularly on the monitor in various spatial combinations. Eye movements were recorded using the electro-oculogram. Possible combinations of visual stimuli in the same or in different visual hemifields. The complex of the positive and negative potentials was revealed in the saccade latent period. Latency of all components was shorter upon presentation of stimuli to the left, unleading eye, that may indicate the earlier saccade preparation. At the same time LP saccades were longer in this conditions (p<0.05). The main asymmetry in saccadic LP was revealed at the presentation of target and distracting stimuli in the left visual hemyfield at the distance 5 degrees between them. The results show that early potentials N1 and P1 were higher in amplitude and dominated in medial and controlateral parietal-occipital areas. It can be reflection of visual sensory processing and processes of motor preparation at the same time. The amplitude of the later negative potential N2 at the stimulation of the right eye increased in the case when target stimulus was at the same location than at the previous realisation. It’s possible that N2 component is connected with processes of preliminary extracting of motor programme from memory together with attention processes. N2 amplitude was higher when the distance between target and distracting stimuli was 15 degrees in comparison with the minimal distance 5 degrees. It’s corresponded with LP data. The findings show an active role of attention and decision-making processes in saccade programming.