Do Perception and Action Result from Different Brain Circuits? The Three Visual Systems Hypothesis

This chapter argues that the separation of the cortical visual processing into two streams is insufficient and, in the version where perception and action are kept separated, leads to a misunderstanding of the true nature of perceptual processes. It shows that the processing carried out in the inferior parietal lobule is different from that performed in the inferior parietal lobe, and that the so-called dorsal stream is in fact formed by two streams: the dorsodorsal stream (D-D) and the ventrodorsal stream (V-D). The chapter also discusses the relation between action and perception as it emerges from neurophysiological data on the V-D stream. It proposes that both action perception and space perception derive from a preceding motor knowledge based on self-generated actions.