Neural correlates of consciousness in the sound-induced flash illusion.
Scientific reports November 28, 2025 Theresa Rieger, Josefine Feuerstein, Niko A Busch et al.
The visual awareness negativity (VAN) is a brain response linked to conscious perception, typically seen when comparing perceived versus unseen visual stimuli. This study tested whether the VAN also appears during visual illusions—when people report seeing something that is not physically present. Using the sound-induced flash illusion, where a single flash accompanied by two beeps often creates the illusion of a second flash, electroencephalography (EEG) was recorded from 47 participants. Comparing illusion trials (where participants reported seeing two flashes) with non-illusion trials (where they saw only one), an enhanced negativity over posterior electrodes was observed between 250 and 300 milliseconds.