Perceptual effects of stimulating V5/hMT+ during binocular rivalry are state specific

Binocular rivalry occurs when two distinct visual stimuli are presented separately to each eye, causing perceptual ambiguity. The conscious state of the observer then alternates between the perceptual dominance of one of the stimuli while the other is suppressed, and vice versa. These vivid changes in perception during constant visual stimulation allow the study of brain processes involved in conscious visual experience. There is abundant electrophysiological as well as fMRI evidence that neural activity in stimulus-selective areas of the temporal lobe correlates with perceptual changes during rivalry [1–3]. Yet, almost nothing is known about the causal contribution of these areas to dominance and suppression of their preferred stimulus. We induced binocular rivalry in human observers using moving dots presented to one eye and a static face to the other eye, and applied transcranial magnetic stimulation (TMS) over the motion area V5/hMT+. We show that disrupting activity in V5/hMT+ during rivalry extends periods of motion suppression, with no effect on periods of motion dominance, revealing a state-specific contribution of V5/hMT+ to the competition for awareness in rivalry.