Tracking rivalry with neural rhythms: Multivariate SSVEPs reveal perception during binocular rivalry

The contents of awareness can substantially change without any modification to the externalworld. Such effects are exemplified in binocular rivalry, where a different stimulus is presented to each eye causing instability in perception. This phenomenon has made binocular rivalry a quintessential method for studying consciousness and the necessary neural correlates for awareness. However, to conduct research on binocular rivalry usually requires self-reports of changes in percept, which can produce confounds and exclude states and contexts where self- reports are undesirable. Here we use a novel multivariate spatial filter dubbed ‘Rhythmic Entrainment Source Separation’ to extract steady state visual evoked potentials from EEG data. We show that this method can be used to very accurately quantify the perceptual switch-rate of participants during binocular rivalry and therefore may be valuable in experimental contexts where self-reports are methodologically problematic or impossible. Our analyses also reveal that “no-report” conditions may affect the deployment of attention and thereby neural correlates; another important consideration for consciousness research.