Abstract

When regions containing a counterphasing sine-wave grating are presented side by side and in spatial and temporal quadrature phase, a transparent perception of motion results. This occurs even though none of the stimulus parts is moving. The two percepts of motion in these displays are in opposite directions, one analogous to brightness contrast, the other to brightness assimilation. If the regions are separated by a gap, the contrast and assimilation motions remain visible for separations up to 0.5 and 1 period, respectively. Both motions occur at temporal frequencies from 1 to 16 Hz. The perceived motion analogous to brightness assimilation is easily modeled with elongated receptive fields that integrate flux along the long axis, such as simple cells. The perceived motion analogous to brightness contrast can be accounted for by receptive fields that subtract the flux in one region from the flux in another region. Examples are center–surround subunits such as are found in the elaborated Reichart model [ W. Reichardt, in Sensory Communication, W. A. Rosenblith, ed. ( MIT Press, Cambridge, Mass., 1961), pp. 303– 317; J. P. H. van Santen and G. Sperling, J. Opt. Soc. Am. A 2, 300– 321 ( 1985)]. The dual perceived motion suggests that more than one kind of motion channel (distinguished by the two-dimensional receptive field of the front-end filter) is present in the human visual system.

© 1995 Optical Society of America

Temporal covariance model of human motion perception

Jan P. H. van Santen and George Sperling
J. Opt. Soc. Am. A 1(5) 451-473 (1984)

Elaborated Reichardt detectors

Jan P. H. van Santen and George Sperling
J. Opt. Soc. Am. A 2(2) 300-321 (1985)

Contrast response of a movement-encoding system

Jüri Allik and Aleksander Pulver
J. Opt. Soc. Am. A 12(6) 1185-1197 (1995)

Motion and metacontrast with simultaneous onset of stimuli

Walter F. Bischof and Vincent Di Lollo
J. Opt. Soc. Am. A 12(8) 1623-1636 (1995)

Computational structure of a biological motion-detection system as revealed by local detector analysis in the fly’s nervous system

Martin Egelhaaf, Alexander Borst, and Werner Reichardt
J. Opt. Soc. Am. A 6(7) 1070-1087 (1989)