The Importance of Spatiotemporal Information in Biological Motion Perception: White Noise Presented with a Step-like Motion Activates the Biological Motion Area.

Humans can easily recognize the motion of living creatures using only a handful of point-lights that describe the motion of the main joints (biological motion perception). This special ability to perceive the motion of animate objects signifies the importance of the spatiotemporal information in perceiving biological motion. The posterior STS (pSTS) and posterior middle temporal gyrus (pMTG) region have been established by many functional neuroimaging studies as a locus for biological motion perception. Because listening to a walking human also activates the pSTS/pMTG region, the region has been proposed to be supramodal in nature. In this study, we investigated whether the spatiotemporal information from simple auditory stimuli is sufficient to activate this biological motion area. We compared spatially moving white noise, having a running-like tempo that was consistent with biological motion, with stationary white noise. The moving-minus-stationary contrast showed significant differences in activation of the pSTS/pMTG region. Our results suggest that the spatiotemporal information of the auditory stimuli is sufficient to activate the biological motion area.