Does the visual mismatch negativity (vMMN) care about eye-of-origin information?

When the eyes are simultaneously presented with dissimilar images, the images alternate in visual perception—binocular rivalry—and an observer cannot tell which image is presented to his or her left or right eye—failure of utrocular discrimination. We wondered if infrequently swapping binocular rivalry stimuli between the eyes would yield the visual mismatch negativity (vMMN)—a negative component of the event-related potential (ERP) technique. The vMMN usually occurs about 150-250 ms after the presentation of an infrequent stimulus (a “deviant”) embedded in a sequence of frequent stimuli (a “standard”). We presented 80% of binocular rivalry standards—one grating to one eye and an orthogonal grating to the other, and 20% of deviants—either by swapping the gratings between the eyes or by rotating the gratings by 45°. We measured ERPs to a 180° phase shift of both gratings (along with the change to the deviant set) every 500 ms. Sixteen participants pressed buttons to record their experiences of binocular rivalry. We made two key findings. First, there was no difference between the standard and the eye-swap deviant in the vMMN range, suggesting that the vMMN does not care about eye-of-origin information. Second, there was a bigger P1, an ERP component between 80-100 ms after onset of the event, for the standard than for either deviant. The P1 reflects sensory and perceptual processing; in this case we suspect it is because of the 180° phase shift of stimuli. We conclude that the vMMN does not care about eye-of-origin information.