Increased gamma-band synchrony precedes switching of conscious perceptual objects in binocular rivalry

Gamma-band neural synchrony has been proposed as a correlate of consciousness and as a solution for the binding problem. Research on visual working memory and the perception of coherent images in ambiguous figures supports this view. To test the relationship between perceptual consciousness and γ synchrony, we recorded electroencephalogram activity while participants were presented with rivalling visual images to each eye. Participants pressed buttons to indicate which image they were perceiving, and response-locked phase-locking values (6–60 Hz) were calculated from the electroencephalogram time series. Results revealed transient bursts of increased global phase synchrony in the γ-band peaking ∼425 and ∼260 ms preresponse. This suggests that global γ synchrony is associated with the emergence of a coherent conscious percept.