Neural Mechanisms for Heading and Structure-from Motion Perception

Two of the most important perceptual functions of the visual motion system are to compute our direction of heading as we move through the environment, and to deduce the three-dimensional structure of objects and the environment from motion cues. Below, we review experiments that provide insights into how these perceptual phenomena are constructed by the brain. Understanding how the motion system performs these analyses will likely have general applicability to other perceptual functions, both within and outside the motion pathway. For instance, understanding how motion signals are perceived as spatially constant despite eye movements, an important prerequisite for determining heading direction, may lead to a general understanding of spatial-perceptual constancy. Likewise, understanding how three-dimensional form is processed from motion cues in the dorsal visual pathway may provide important suggestions as to how form is derived from other visual cues in the ventral visual pathway.