Multisensory interactions of audiovisual stimuli presented at different locations in auditory-attention tasks: A event-related potential (ERP) study

We applied behavioral and event-related potential (ERP) measures to study the multisensory interactions of audiovisual stimuli presented at different locations in an auditory-attention task in which an irrelevant visual stimulus occasionally accompanied the auditory stimulus. A stream of visual (V), auditory (A), spatially congruent audiovisual (AVCon), and spatially incongruent audiovisual (AVInc) stimuli were randomly presented to the left and/or right side; subjects covertly attended to the auditory stimuli on either the left or right side and promptly responded to auditory targets on that side. In present study, we only investigated the results which were related with multisensory interactions of audiovisual stimuli presented at different locations. ERPs to A, V_Inc which is at opposite locations with A, and AV_Inc stimuli were recorded. The neural basis of multisensory interactions of audiovisual stimuli presented at different location was studied by comparing ERPs to the AVJnc stimuli with the sum of the ERPs to the unimodal A and Vine stimuli. ERPs results showed that main audiovisual interactions were found as a negativity in mid-central scalp sites around a latency of 300 ms during the later stage of processing. The present results revealed the neural basis of multisensory interaction of audiovisual stimuli presented at different locations in an auditory-attention task. The study can offer base data for multi-sensor data fusion algorithms and robotics.