Structural and functional fractionation of right superior parietal cortex in bistable perception

When faced with ambiguous sensory input, conscious awareness may alternate between the different percepts that are consistent with the input. Visual phenomena leading to such multistable perception, where constant sensory input evokes different conscious percepts, are particularly useful for investigating the processes underlying perceptual awareness [1]. Understanding the role that high-level brain regions outside early visual cortex play in perceptual alternations could elucidate how top-down processes modulate conscious perception [2]. In two studies [3,4] published recently in Current Biology, different combinations of the present authors used repetitive transcranial magnetic stimulation (rTMS) to disrupt activity in human superior parietal cortex, and reported seemingly contradictory results [5] concerning the effect of disrupting the normal function of this area on bistable perception. Here we join forces to resolve this discrepancy.