Suppression of the auditory N1 by visual anticipatory motion is modulated by temporal and identity predictability.

The amplitude of the auditory N1 component of the event-related potential (ERP) is typically suppressed when a sound is accompanied by visual anticipatory information that reliably predicts the timing and identity of the sound. While this visually induced suppression of the auditory N1 is considered an early electrophysiological marker of fulfilled prediction, it is not yet fully understood whether this internal predictive coding mechanism is primarily driven by the temporal characteristics, or by the identity features of the anticipated sound. The current study examined the impact of temporal and identity predictability on suppression of the auditory N1 by visual anticipatory motion with an ecologically valid audiovisual event (a video of a handclap). Predictability of auditory timing and identity was manipulated in three different conditions in which sounds were either played in isolation, or in conjunction with a video that either reliably predicted the timing of the sound, the identity of the sound, or both the timing and identity. The results showed that N1 suppression was largest when the video reliably predicted both the timing and identity of the sound, and reduced when either the timing or identity of the sound was unpredictable. The current results indicate that predictions of timing and identity are both essential elements for predictive coding in audition.