An ERP Study on Sound-contingent Visual Motion Perception

Recent studies have demonstrated that a new association between auditory sequence and visual motion can be rapidly formed even in adults (sound-contingent visual motion perception: SCVM). The present study investigated the neural mechanisms underlying SCVM using event-related potential (ERP). During a 9-min exposure phase, two circles placed side-by-side were alternately and repeatedly presented to produce horizontal apparent motion. The onsets of the circles were synchronized with highand low-frequency tones. ERPs were measured before and after the exposure phase in response to a pair of visual stimuli (S1 and S2) sequentially presented at a fixed location with a sound sequence that contained the same high and low frequency tones as presented during the exposure phase. After the exposure, the participants experienced SCVM. Significant ERP differences between the preand post-exposure were observed not only in the S2 presentation, but also in the S1 presentation. These findings suggest that SCVM processing starts in higher stages of the visual system as early as S1 presentation and then sends feedback signals to earlier stages to induce motion perception at S2 presentation.