Abstract
Binocular rivalry is a phenomenon created by presenting similar but different images for each eyes simultaneously. In recent studies, it is supposed that competitive interactions of information process occurred at not only lower levels, but also higher levels of the visual cortices. However, most of those studies mainly focused at an alternation of the perception, and visual responses itself under binocular rivalry have not been studied enough. In this study, higher level visual responses were investigated using various types of binocular rivalry stimuli. Three types of pattern appearance stimuli which caused direction, motion direction, and color binocular rivalry were used. Stimuli were displayed with a liquid crystal shutter, and only one type of binocular rivalry was evoked under a natural visual condition. VEFs (Visual Evoked Fields) were recorded with a MEG (Magnetoencephalography) system. In order to analyze the data, we used two evaluation values, the ratio of RMS (Root Mean Square) and the correlation coefficient between rivalry and non-rivalry conditions. These values specified the responses of binocular rivalry efficiently, and the responses of each rivalry were specified at 350ms or later after the pattern appeared. Most of the iso-contour maps of each rivalry were appeared to be similar patterns, and source localizations resulted at the vicinity of PP (Posterior Parietal) for direction, MT (Middle Temporal) for motion direction, and IT (Inferior Temporal) for color rivalry respectively. The results were very well in agreement with electro-physiological experiments with macaque monkeys.