Electrophysiological (EEG, sEEG, MEG) evidence for multiple audiovisual interactions in the human auditory cortex

In this review, we examine the contribution of human electrophysiological studies (EEG, sEEG and MEG) to the study of visual influence on processing in the auditory cortex. Focusing mainly on studies performed by our group, we critically review the evidence showing (1) that visual information can both activate and modulate the activity of the auditory cortex at relatively early stages (mainly at the processing stage of the auditory N1 wave) in response to both speech and non-speech sounds and (2) that visual information can be included in the representation of both speech and non-speech sounds in auditory sensory memory. We describe an important conceptual tool in the study of audiovisual interaction (the additive model) and show the importance of considering the spatial distribution of electrophysiological data when interpreting EEG results. Review of these studies points to the probable role of sensory, attentional and task-related factors in modulating audiovisual interactions in the auditory cortex.