The human visual system differentially represents subjectively and objectively invisible stimuli

Abstract

TAU he s:tuPdleyaosef cuonncfoirnmstchiaotuasllhperaodciensgsleinvgelsraerqeurierpersesaemnteedacsourrreecotlfyc:onscious awareness. Awareness measures can be either subjective (based on participant's report) or objective (based on perceptual performance). The preferred awareness measure depends on the theoretical position about consciousness and may influence conclusions about the extent of unconscious processing and about the neural correlates of consciousness. We obtained functional magnetic resonance imaging (fAMURI:)PmleeaasseunroetemtheantftMs fRroIhmas4b3eesnudbejfeincetsdawshfuilnectthioenyalvmieawgneedticresonanceimaginginsentencesWeobtainedfunctionalmagneticresonanmasked faces and houses that were either subjectively or objectively invisible. Even for objectively invisible (perceptually indiscriminable) stimuli, we found significant category information in both early, lower-level visual areas and in higher-level visual cortex, although representations in anterior, category-selective ventrotemporal areas were less robust. For subjectively invisible stimuli, similar to visible stimuli, there was a clear posterior-To-Anterior gradient in visual cortex, with stronger category information in ventrotemporal cortex than in early visual cortex. For objectively invisible stimuli, however, category information remained virtually unchanged from early visual cortex to object-and category-selective visual areas. These results demonstrate that although both objectively and subjectively invisible stimuli are represented in visual cortex, the extent of unconscious information processing is influenced by the measurement approach. Furthermore, our data show that subjective and objective approaches are associated with different neural correlates of consciousness and thus have implications for neural theories of consciousness.