Spatial modulation of auditory-somatosensory interactions: effects of stimulated body surface and acoustic spectra

Conference poster, 2008

Recent research on auditory-somatosensory interactions has shown contradictory results regarding the spatial modulation. In the present study we report on three experiments on auditory-somatosensory interactions in the region close to the head. Participants made speeded simple detection responses to single auditory, somatosensory or double simultaneous auditory-somatosensory stimuli. In Experiment 1, electrocutaneous stimuli were presented to either earlobe, while auditory stimuli were presented from the same versus different sides, and from one of two distances (20 or 70 cm) from the participant’s head. The results demonstrated a spatial modulation of auditory-somatosensory interactions, especially when auditory stimuli were presented from close to the head. Experiment 2, with electrocutaneous stimuli delivered to the hands (placed either close to, or far from, the participants’ head), suggests that the spatial modulation is dependent on the particular body part stimulated (head) rather than on the region of space (around the head) where the stimuli is presented. Experiment 3 showed that this auditory-somatosensory spatial effect occurs primarily for sounds containing high-frequency components. Taken together, these results suggest that the auditory-somatosensory multisensory integration might be facilitated by stimuli occurring at the same location, and that this integration is modulated by the stimulated body surface and acoustic spectra.