Noory Babak, Herzog Michael H, Ogmen Haluk
Department of Electrical and Computer Engineering, University of Houston, Houston, TX, USA.
Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland.
Vision Res. 2015 Aug;113(Pt A):44-54. doi: 10.1016/j.visres.2015.05.010. Epub 2015 Jun 3.
Many visual attributes of a target stimulus are computed according to dynamic, non-retinotopic reference frames. For example, the motion trajectory of a reflector on a bicycle wheel is perceived as orbital, even though it is in fact cycloidal in retinal, as well as spatial coordinates. We cannot perceive the cycloidal motion because the linear motion of the bike is discounted for. In other words, the linear motion common to all bicycle components serves as a non-retinotopic reference frame, with respect to which the residual (orbital) motion of the reflector is computed. Very little is known about the underlying mechanisms involved in formation and operation of non-retinotopic reference frames. Here, we investigate spatial properties of non-retinotopic reference frames. We show that reference frames are not restricted within the boundaries of moving stimuli but extend over space. By using a variation of the Ternus-Pikler paradigm, we show that the spatial extent of a non-retinotopic reference frame is independent of the size of the inducing elements and the target position near the object boundary. While dynamic reference-frames interact with each other significantly, a static reference-frame has no effect on a dynamic one. The magnitude of interactions between two neighboring dynamic reference-frames increases as the distance between them reduces. Finally, our results indicate that the reference-frame strength is significantly attenuated if the locus of attention is shifted to the elements of the neighboring reference instead of the main reference. We suggest that these results can be conceptualized as reference frames that act and interact as fields.
目标刺激的许多视觉属性是根据动态的、非视网膜拓扑参考框架来计算的。例如，自行车车轮上反射器的运动轨迹被感知为轨道运动，尽管其在视网膜以及空间坐标中实际上是摆线运动。我们无法感知到摆线运动，因为自行车的直线运动被剔除了。换句话说，所有自行车部件共有的直线运动充当了一个非视网膜拓扑参考框架，相对于这个框架来计算反射器的剩余（轨道）运动。关于非视网膜拓扑参考框架的形成和运作所涉及的潜在机制，我们知之甚少。在这里，我们研究非视网膜拓扑参考框架的空间特性。我们表明，参考框架并不局限于移动刺激的边界内，而是延伸到空间中。通过使用特尔努斯 - 皮克勒范式的一种变体，我们表明非视网膜拓扑参考框架的空间范围与诱导元素的大小以及物体边界附近的目标位置无关。虽然动态参考框架之间会显著相互作用，但静态参考框架对动态参考框架没有影响。两个相邻动态参考框架之间相互作用的强度会随着它们之间距离的减小而增加。最后，我们的结果表明，如果注意力的焦点转移到相邻参考的元素而不是主要参考的元素上，参考框架的强度会显著减弱。我们认为，这些结果可以被概念化为像场一样起作用和相互作用的参考框架。
