Neural signatures of visual awareness independent of postperceptual processing.
Cerebral cortex (New York, N.Y. : 1991) November 5, 2024 Michael A Cohen, Cole Dembski, Kevin Ortego et al. 20 citations
Using electroencephalography and a no-report visual masking paradigm, stimulus visibility was manipulated by varying the time between stimuli and masks in linear steps (17, 33, 50, 67, and 83 ms). Awareness increased nonlinearly, with stimuli never seen at the two shortest intervals, always seen at the two longest, and 50% seen at the intermediate interval. A neural signal closely linked to perceptual awareness, independent of task, was identified: a fronto-central event-related potential called the N2 (~250 to 300 ms). Earlier signals reflected the linear manipulation of stimulus strength, while later signals like P3b and temporal generalization of decoding were tied to task performance, appearing only in the report condition. These findings inform debates regarding theories of consciousness.