A late meta-stable code of conscious access in the absence of report

One of the most widely recognised neural correlates of consciousness, the P3b, has been challenged in recent years as a neural signal linked to conscious processing, due to its absence in no-report paradigms. Here, we test whether, even in the absence of a P3b, a period of late metastable brain activity may provide a more general signature of conscious access to perceptual information. To this end, we leverage modern advances in electroencephalography (EEG) analyses, re-examining four datasets from no-report inattentional blindness experiments--all of which failed to find a P3b for consciously seen task irrelevant stimuli-- using cross-time multivariate decoding analyses on the EEG data. We find robust temporal generalization of decoding for consciously seen stimuli across different stimulus types (shapes, faces, words), independent of report requirements and regardless of whether a P3b was evoked. This temporal generalization occurred most consistently 200-400 milliseconds post-stimulus onset, suggesting a meta-stable neural code for conscious processing in a time window typically associated with cognitive access to perceptual content. These consistent temporal generalization patterns across stimulus types indicate a potentially universal signature of conscious access.