Abstract
Perceptual multi-stability is characterized by alternating interpretations of stable stimulus input. The time-course and nature of neural processes related to these endogenous perceptual reversals have been studied with event-related potentials by measuring the Reversal Negativity (RN) and the Reversal Positivity (RP) components. However, it is debated to what extent these components reflect perceptual processes or top-down, task-related processes. To address this issue, we presented ambiguous Necker Lattice and Rubin’s Faces-Vase stimuli under two different task conditions. In the standard reversal task used in previous studies, participants indicated whether or not they saw a perceptual reversal on each trial. In contrast, in the identity task, participants reported the perceived orientation of the stimulus in the Necker Lattice experiment and whether they saw faces or a vase in the Face Vase experiment without any reference to reversals. We found that the RN component appeared independently of the task and for both stimuli. However, the early latency RP component was only present on trials where participants responded manually. For non-response trials, the polarity of this effect was reversed. Our results suggest that the early RP component is sensitive to response-related processes and thus is not a neural signature of pure stimulus processes related to endogenous perceptual reversals.