Replay experiment. To estimate reaction time to the perceptual change, a replay experiment was conducted, in which the stimuli were physically modulated to simulate the perceptual time course recorded in the CFS experiment. To mimic the invisible phase, the wedge was physically removed. To mimic the visible phase, the wedge was presented to the nondominant eye and the contrast of the corresponding region of the Mondrian was decreased by a two-dimensional Gaussian window of full width at half maximum 5.5°, making the wedge visible. To mimic the perceptual switch, the contrasts of the stimuli were increased or decreased with a linear ramp of 200 ms. Subjects were instructed to report the visibility of the wedge as described in Subjects' task. Reaction time, from the end of the contrast increment or decrement to the key press, was measured. The reaction time **data** were pooled across subjects; reaction times longer than 2,000 ms were excluded. Median reaction times for the physical appearance and disappearance of the wedges were calculated separately (692 ms and 456 ms, respectively) and their distributions were modeled with ex-Gaussian functions ( Fig. 2E; appearance: ϭ 446.5, ϭ 186.6, ϭ 297.4; disappearance: ϭ 199.8, ϭ 94.6, ϭ 356.0; for details on ex-Gaussian function see Lacouture and Cousineau 2008;Saiki et al. 2011). The median reaction times were subtracted from the raw key press time courses to compensate for the delay between the perceptual change and the key press in the following fMRI analysis. The distributions of the reaction times were used in a simulation described below (see Contamination control).