Perceived Direction of Motion Determined by Adaptation to Static Binocular Images

Keith A May,Paul B Hibbard,Li Zhaoping

doi:10.1016/j.cub.2011.11.025

Keith A May, Paul B Hibbard + Show 1 more

Open Access

https://doi.org/10.1016/j.cub.2011.11.025

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Abstract

In Li and Atick's [1, 2] theory of efficient stereo coding, the two eyes' signals are transformed into uncorrelated binocular summation and difference signals, and gain control is applied to the summation and differencing channels to optimize their sensitivities. In natural vision, the optimal channel sensitivities vary from moment to moment, depending on the strengths of the summation and difference signals; these channels should therefore be separately adaptable, whereby a channel's sensitivity is reduced following overexposure to adaptation stimuli that selectively stimulate that channel. This predicts a remarkable effect of binocular adaptation on perceived direction of a dichoptic motion stimulus [3]. For this stimulus, the summation and difference signals move in opposite directions, so perceived motion direction (upward or downward) should depend on which of the two binocular channels is most strongly adapted, even if the adaptation stimuli are completely static. We confirmed this prediction: a single static dichoptic adaptation stimulus presented for less than 1 s can control perceived direction of a subsequently presented dichoptic motion stimulus. This is not predicted by any current model of motion perception and suggests that the visual cortex quickly adapts to the prevailing binocular image statistics to maximize information-coding efficiency.

Highlights

We ran three experiments to investigate the effect of binocular adaptation on the perceived direction of a dichoptic motion test stimulus based on that of Shadlen and Carney [3]
Each eye received a flickering horizontal grating pattern that had no net motion in any direction, but the summation (S+) and difference (S2) signals were smoothly drifting gratings that moved in opposite directions
Our results follow naturally from the proposal of independently adaptable binocular summation and differencing channels that are central to Li and Atick’s [1, 2] theory of efficient stereo coding

Summary

Introduction

We ran three experiments to investigate the effect of binocular adaptation on the perceived direction of a dichoptic motion test stimulus based on that of Shadlen and Carney [3]. To selectively adapt the summation or differencing channels (which are sketched out in Figure 1) prior to presentation of the test stimulus, we presented static binocular stimuli that were either identical or contrast reversed between the eyes.

Results

Conclusion