Crossmodal effect with rubber hand illusion and gamma-band activity.

The integration of multimodal stimuli has been regarded as important for the promotion of adaptive behavior. Although recent work has identified brain areas that respond to multimodal stimuli, the temporal features are not clear yet. Earlier event-related potential studies revealed crossmodal attention effects, but did not focus on mechanisms underlying crossmodal integration. Here, electroencephalography (EEG) activity in the gamma band was considered as a correlate of multimodal integration. Participants localized a tactile stimulus on their fingers while seeing visual stimuli on rubber hands with the same posture as their hands. EEG analyses using wavelet transform suggested that interelectrode phase synchrony in the gamma-band range (40-50 Hz) was related to behavioral indices of the intermodal illusion under consideration. The findings suggest a role of high-frequency oscillations in the integrative processing of stimuli across modalities.