[Effect of support removal on pre-saccadic EEG potentials in test-subjects with various asymmetry profiles]

Saccades and slow pre-saccadic potentials were investigated in 12 volunteered test-subjects (7 subjects with the leading right eye (RE-group) and 5 subjects with the leading left eye (LE-group) before and after 6-d DI experiment. Visual stimulation was provided with 3 LEDs one of which was located centrally in the field of vision and the other two - 10 degrees left and right along the horizontal axis. The subjects performed the test for antisaccades requiring to produce saccades toward a point symmetrical to displayed stimulus. EEG (monopolar in 19 standard leads) and electrooculogram were registered. Peripheral stimulus activation served as a trigger for backward averaging as a method to obtain slow pre-saccadic potentials (PSPs). Testing before immersion did not reveal any noteworthy differences in saccades produced by the members of both groups. At the same time, amplitude of pre-saccadic negativity (PSN) in LE-group was lower, especially in the frontal region of head, and distinguished by apparent asymmetry throughout the period of analysis. In immersion, latent saccades and percentage of erroneous reactions did not change in the RE-group but increased in the LE-group. Both groups reduced the PSN amplitudes shifting PSN to the right cerebral hemisphere; differences between the groups were masked by immersion. The RE-group was marked by a reliable decline of the PSN amplitude in the frontal leads due to, probably, sensory disintegration and reduced tonic afferentation in immersion. In the LE-group, maximum PSN amplitude was registered in the central region of head equally before and during immersion.