Perception of self-motion from visual flow

Accurate and efficient control of self-motion is an important requirement f or our daily behavior, Visual feedback about self-motion is provided by opt ic flow. Optic flow can be used to estimate the direction of self-motion (' heading') rapidly and efficiently. Analysis of oculomotor behavior reveals that eye movements usually accompany self-motion. Such eye movements introd uce additional retinal image motion so that the flow pattern on the retina usually consists of a combination of self-movent. movement components. The question of whether this 'retinal flow' alone allows the brain to estimate heading, or whether an additional 'extraretinal' eye movement signal is nee ded, has been controversial. This article reviews recent studies that sugge st that heading can be estimated visually but extraretinal signals are used to disambiguate problematic situations. The dorsal stream of primate corte x contains motion processing areas that are selective for optic flow and se lf-motion. Models that link the properties of neurons in these areas to the properties of heading perception suggest possible underlying mechanisms of the visual perception of self-motion.