Klimova, Oxana A.

Relevance. The study of the self-motion (“vection”) illusion is an important task for modern psychology and neuroscience due to the widespread use of virtual reality systems. The study of psychophysiological mechanisms of this phenomenon has particular importance as an example of intersensory interactions.

Objective. To study the psychophysiological mechanisms of the self-motion illusion in a virtual reality system using electroencephalography.

Methodology. Eleven healthy subjects took part in the experiment. The stimulation was a virtual opto-kinetic drum that rotated clockwise and counterclockwise around a vertical axis with angular velocities of 30, 45 and 60 angular deg/s. The duration of each rotation was 60 seconds. The subjects were presented with 18 rotations; there was a series with instructions for free viewing of the visual scene (3 speeds × 2 directions × 2 repetitions) and a series with instructions to fix the gaze in the center of the virtual scene (3 speeds ×2 directions × 1 repetition). After each rotation, the subjects filled out the “Simulator Sickness Questionnaire” and evaluated the intensity of the illusion on a 10-point scale. Stimulation was presented in the HTC Vive virtual reality helmet. Electroencephalogram recording during the observation of cylinder rotations was performed using Mitsar-EEG-10/70-201.

Results. Significant differences were found in the intensity of the illusion, the total score on the questionnaire, and the power of the alpha rhythm in the parietal zones, depending on the speed of rotation. The higher the rotational speed, the greater the values of these dependent variables. Large values for beta-rhythm power in the occipital areas were found in the series with fixed eyes, in the subjects with high values for the intensity of the illusion.

Conclusions. Differences were shown in the bioelectrical activity of the brain during the experience of the self-motion illusion, related to mechanisms of visual-vestibular integration and greater attention to the performance of the motor task of gaze fixation.