Terao Masahiko, Nishida Shin'ya
The research Institute for Time Studies, Yamaguchi University.
NTT Communication Science Laboratories, Kyoto, Japan; Graduate School of Informatics, Kyoto University.
Iperception. 2020 Jun 26;11(3):2041669520937320. doi: 10.1177/2041669520937320. eCollection 2020 May-Jun.
Many studies have investigated various effects of smooth pursuit on visual motion processing, especially the effects related to the additional retinal shifts produced by eye movement. In this article, we show that the perception of apparent motion during smooth pursuit is determined by the interelement proximity in retinal coordinates and also by the proximity in objective world coordinates. In Experiment 1, we investigated the perceived direction of the two-frame apparent motion of a square-wave grating with various displacement sizes under fixation and pursuit viewing conditions. The retinal and objective displacements between the two frames agreed with each other under the fixation condition. However, the displacements differed by 180 degrees in terms of phase shift, under the pursuit condition. The proportions of the reported motion direction between the two viewing conditions did not coincide when they were plotted as a function of either the retinal displacement or of the objective displacement; however, they did coincide when plotted as a function of a mixture of the two. The result from Experiment 2 showed that the perceived jump size of the apparent motion was also dependent on both retinal and objective displacements. Our findings suggest that the detection of the apparent motion during smooth pursuit considers the retinal proximity and also the objective proximity. This mechanism may assist with the selection of a motion path that is more likely to occur in the real world and, therefore, be useful for ensuring perceptual stability during smooth pursuit.
许多研究调查了平稳跟踪对视觉运动处理的各种影响，尤其是与眼球运动产生的额外视网膜位移相关的影响。在本文中，我们表明，平稳跟踪过程中对似动的感知由视网膜坐标中的元素间接近度以及客观世界坐标中的接近度决定。在实验1中，我们研究了在注视和跟踪观察条件下，具有不同位移大小的方波光栅的两帧似动的感知方向。在注视条件下，两帧之间的视网膜位移和客观位移相互一致。然而，在跟踪条件下，位移在相移方面相差180度。当将两种观察条件下报告的运动方向比例作为视网膜位移或客观位移的函数绘制时，它们并不一致；然而，当作为两者混合的函数绘制时，它们是一致的。实验2的结果表明，似动的感知跳跃大小也取决于视网膜位移和客观位移。我们的研究结果表明，平稳跟踪过程中对似动的检测既考虑视网膜接近度，也考虑客观接近度。这种机制可能有助于选择在现实世界中更可能出现的运动路径，因此，有助于确保平稳跟踪过程中的感知稳定性。
