Binocular rivalry is partly resolved at early processing stages with steady and with flickering presentation: a human event-related brain potential study.

When their two eyes are presented with radically different images, observers report a fluctuation in perception between those images. This phenomenon, i.e. that only one image dominates the percept at a time, is termed binocular rivalry. Consequently, when rivalrous stimulation is changed into non-rivalrous stimulation, it depends on the image that has been currently dominant whether a change in perception occurs (incompatible change) or not (compatible change). That is, the perceptual experience differs although the physical input is the same, namely the stimulus of one eye has been changed. In the event-related brain potential (ERP) to compatible and incompatible changes we found differences as early as in the P1-N1-range, suggesting that in humans the binocular rivalry phenomenon is already (partly) resolved in extrastriate visual areas latest. Moreover, similar results were obtained with steady and flickering stimulus presentation showing that the processes involved in dealing with competing visual input do not depend critically on stimulus presentation mode.