Institute of Experimental Psychology, University of Regensburg, Regensburg, Germany.
Department of Psychology, National Taiwan University, Taipei, Taiwan.
J Vis. 2020 Sep 2;20(9):5. doi: 10.1167/jov.20.9.5.
The perception of a target stimulus may be altered by its context. Perceptual filling-in is thought to be one example of lateral modulation, in which the percept of a central blank area is replaced by that of the surround. We investigated the mechanisms in eccentric vision underlying filling-in by selectively adapting the center (pedestal adapter), surround (annulus adapter), or both (disk adapter) in a sinusoidal grating and observed how the adaptation influences the orientation percept of a subsequently presented Gabor target, located at the same position as the adapter center. In a binary choice task, observers were to judge the orientation (clockwise or counterclockwise) of the target after adaptation. The tilt aftereffect (TAE), corresponding to an illusory tilt of a physically vertical Gabor target, depended both on the adapter orientation and the adapter type. The TAE, peaked between 10 degrees and 20 degrees adapter orientation, was strongest in the pedestal, followed by the disk, and weakest in the annulus adapter conditions. The difference between the disk and pedestal conditions implies lateral inhibition from the surround. Lacking physical overlap with the target, the annulus adapter nonetheless induced a small but significant TAE in the central area. The effect of filling-in on the TAE was estimated by comparing the results from trials with and without subjectively reported filling-in during adaptation to the annulus adapter. The TAE was greater when filling-in occurred during adaptation, suggesting a stronger lateral modulation effect on trials where filling-in was induced. The data were fit by a variant of a divisive inhibition model, in which the adaptation effect is captured by the increase of an additive constant in the denominator of the response function, whereas the surround modulation in the adapter is modeled by an excitatory sensitivity in the numerator.
目标刺激的感知可能会因其所处的环境而发生改变。人们认为，感知填补就是侧抑制的一个例子，即中央空白区域的感知被周围区域的感知所取代。我们通过选择性地在正弦光栅中适应中心（基座适配器）、周围（环适配器）或两者（盘适配器），来研究偏心视觉中的填充机制，并观察适应如何影响随后呈现的位于适配器中心位置的 Gabor 目标的方向感知。在二进制选择任务中，观察者在适应后判断目标的方向（顺时针或逆时针）。倾斜后效（TAE），对应于物理垂直 Gabor 目标的虚幻倾斜，既取决于适配器的方向，也取决于适配器的类型。TAE 在适配器方向 10 度到 20 度之间达到峰值，在基座适配器条件下最强，其次是盘适配器，环适配器条件下最弱。盘适配器和基座适配器条件之间的差异意味着来自周围的侧抑制。环适配器与目标没有物理重叠，但仍会在中央区域引起较小但显著的 TAE。通过比较适应环适配器时主观报告有和没有填充的试验结果来估计填充对 TAE 的影响。当适应期间发生填充时，TAE 更大，这表明在诱导填充的试验中，侧抑制的影响更强。数据符合一种抑制性分离模型的变体，该模型通过在响应函数的分母中增加一个附加常数来捕获适应效果，而适配器中的周围调制则通过分子中的兴奋性灵敏度来建模。
