An event-related potential investigation of the time-course of temporal ventriloquism

Temporal ventriloquism refers to the phenomenon that a sound presented in close temporal proximity of a visual stimulus attracts its perceived temporal occurrence. Here, we investigate the time-course of the neuronal processes underlying temporal ventriloquism, using event-related brain potentials. To measure shifts in perceived temporal visual occurrence, we used a paradigm in which a sound modulates the magnitude of a visual illusion called the flash-lag effect. A sound presented before the flash reduced both the size of the flash-lag effect and the amplitude of visual N1 compared with when the sound lagged the flash. We attribute the modulation of the flash-lag effect to a modulation of facilitation of visual processing. The time-course (190 ms) and localization (occipitoparietal cortex) of this particular auditory-visual interaction confirms the sensory nature of temporal ventriloquism.