Identifying Content-Invariant Neural Signatures of Perceptual Visibility

Abstract

Some conscious experiences are more vivid than others. Although perceptual visibility is a familiar component of human consciousness, how variation in visibility is registered by the human brain is unknown. In particular, it is unknown whether the vividness of experience is encoded in a rich manner, via the strengthening or broadcast of content-specific perceptual representations, or a sparse manner, in which content-invariant signals track the reliability or precision of perceptual contents. Here we reanalysed existing MEG and fMRI data from two distinct studies, operationalising perceptual visibility as subjective ratings of awareness and visibility. Using representational similarity and decoding analyses, we find evidence supporting a proposal that perceptual visibility is associated with content-invariant neural signatures distributed across visual, parietal, and frontal cortices. Our findings are consistent with content-invariant neural substrates supporting the strength of perceptual experience and offer a novel methodology for examining the neural correlates of perceptual awareness.