Lead selection for SSVEP-based binocular rivalry

In binocular rivalry, a subject views two incongruent stimuli through each eye but consciously perceives only one stimulus at a time, with a switch in perceptual dominance every few seconds. To investigate the continuous alternations in perceptual dominance across eyes objectively, thirteen subjects were recorded with 64-channel electroencephalograph while experiencing binocular rivalry. A blue vertical grating flickering at one frequency was presented to one eye and a blue horizontal grating flickering at a different frequency was presented to the other eye. Steady state evoked potential (SSVEP) at the two frequencies were used as tags for the two stimuli. SSVEP-based binocular rivalry has potential advantage of registering the alternation in physiological dominance of the two eyes. This paper presents a method of lead selection to improve the applicability of SSVEP-based binocular rivalry. Optimal lead is selected by comparing signal strength at two stimulus frequencies during rivalry dominance and rivalry suppression. The method with one optimal lead correlates better with the subjects´ report of perceptual dominance.