Dynamic theory of action-perception patterns: the "moving room" paradigm.

Action-perception patterns are studied theoretically in terms of equations of motion that capture the coordination capacity of the nervous system. We consider intrinsic dynamics in the absence of visual information that contain a single posture state as a fixed point attractor. We couple these intrinsic dynamics to visual information that stabilizes posture in the visual world. This leads to a theory of postural sway induced by an optic flow field ("moving room" paradigm). The optic flow is parametrized in a simplest approximation by the expansion rate of a relevant perceptual target. We show how temporal stability as the key concept of this theory can lead to prediction and serve as a measure of perceptual coupling. Finally, we discuss the relation of the present theory to biological cybernetics.