Influences of auditory stimuli in front and rear space on visual detection: An event-related potential study

Although many previous studies have investigated location of modalities could affect detection to the task, whether auditory stimuli in the rear space could influence visual detection remain unclear. Therefore, we designed a visual detection task that included visual stimuli which were presented in front of the participants, auditory stimuli which were presented at one location in an equidistant horizontal plane at the front (0°, the fixation point), right (90°), rear (180°), or left (270°) of the participants, and audiovisual stimuli that both visual stimuli and auditory stimuli from one speaker of the four locations were simultaneously presented. The task of participants is to attend to the visual stimulus and respond promptly only to visual target stimuli (unimodal visual target stimulus and visual target of audiovisual stimulus). We found that auditory stimuli in both the front and rear space could enhance visual detection. Moreover, main event-related potential (ERP) components which influences of auditory stimuli on visual detection were found: (1) over the right occipital area, approximately 160-200 milliseconds, when auditory stimuli were presented in front space; (2) over the parieto-occipital area, approximately 360-400 milliseconds, when auditory stimuli were presented in both front and rear space. Our results confirmed that even though auditory stimuli were presented at rear of the subject, auditory stimuli also could influence visual cognitive in the visual detection task.