N1 Suppression to Audiovisual Self-generated Sensory Events.

The ability to discriminate between self-generated and externally generated events is crucial for adaptive behavior. Attenuated N1 responses to self-initiated sensory events indicate a successful discrimination process based on internal prediction models. The sensory attenuation in the N1 (and P2) component has been shown across different sensory modalities (audition, vision, touch), emphasizing the modality independence of the underlying mechanism. However, N1 sensory attenuation was only studied in isolation across different sensory modalities, although self-generated actions in everyday life typically produce multisensory consequences. Moreover, internal prediction models propose modality-specific predictions, making it particularly interesting to examine sensory attenuation when multiple sensory consequences occur simultaneously. Therefore, the current study investigated the N1 (and P2) sensory attenuation using self-initiated audiovisual stimuli known to be the most frequent combination of sensory events in our environment. Two EEG studies were conducted using different visual stimuli (i.e., Gabor patches vs. checkerboard reversals), each combined with tones. Each study compares the N1 sensory attenuation for unisensory stimulus presentation (only visual stimuli or auditory tones) with the multisensory presentation of audiovisual sensory events. Multisensory audiovisual stimuli elicited N1 attenuation comparable with the attenuation observed for unisensory auditory stimuli. In contrast, no N1 attenuation was observed for unisensory visual stimuli. These findings may be consistent with the presence of parallel, action-dependent mechanisms operating across modalities in the present paradigm. However, they do not permit a clear distinction between existing theoretical accounts on sensory attenuation.