Visual-Vestibular Interaction for Human Ego-Motion Perception

Abstract

Both vestibular and visual cues are known to contribute to human ego-motion perception in space. While the vestibular system registers actual head motion in space, the visual system records in many situations only the relative head-vs-scene motion; then it signals head motion in space only if the scene is stationary. * The use of both cues is probably not merely a matter of redundancy for at least two reasons: (1) Imperfection of the vestibular system; for example, the horizontal canal system fails to register low frequency and constant-velocity head motion. (2) Ambiguity of visual cues; although the visual scene is stationary in most situations of every day life, there are situations in which the visual field, or large parts of it, are filled with moving objects which, when taken as a stationary reference, would create an illusory perception of ego-motion. Therefore, it would be desirable to dismiss visual ego-motion cues whenever the visual scene is moving, and to restrict the use of these cues to conditions where vestibular information deteriorates or is missing. The intriguing problem then is how to detect whether the visual scene is stationary or not. If detection of scene motion is based on vestibular cues, what happens if, for example, the vestibular system fails to distinguish between body stationarity and body motion of constant or low speed?