Low-level luminance mechanisms and the twostage perception of biological motion

The visual system has robust sensitivity to biological motion defined by point-light displays. However, specific aspects of the mechanisms involved in biological motion detection have yet to be explicated. This series of experiments was designed to determine the neural correlates of biological motion perception relative to the convergence of the ON- and OFF- visual pathways. In their study, van der Smagt and van der Grind (1999) suggested that local motion processing occurs prior to the convergence of the ON- and OFF-pathways. For the first time, the data reported here shows that at least some component of biological motion processing arises at that level, that is, in area V1. This study also provides evidence that supports the idea that there may be more than one stage of biological motion processing.