Opposing roles of sensory and parietal cortices in awareness in a bistable motion illusion

Motion-induced blindness (MIB) is a bistable visual phenomenon in which stationary disks surrounded by a moving pattern intermittently disappear from the viewer's awareness. We explored the cortical network that subserves the MIB phenomenon by targeting its constituent parts with disruptive transcranial magnetic stimulation (TMS), in the form of continuous theta burst stimulation (cTBS). Previous neuroimaging and TMS studies have implicated the right posterior parietal cortex (rPPC) in perceptual transitions such as binocular rivalry, while the visual area V5/MT has been suggested to play a key role in MIB. In this study, we found that cTBS applied to the rPPC lengthened the duration of disappearance in MIB, while cTBS applied to V5/MT shortened the duration of disappearance and decreased the frequency of disappearance in MIB. These results demonstrate a causal role for both the rPPC and V5/MT in MIB, and suggest that the rPPC is involved in shifting resources between competing functional areas, while V5/MT processing initiates and maintains MIB.