Toet A, Levi D M
Institute for Perception, TNO Vision Group, DE Soesterberg, The Netherlands.
Vision Res. 1992 Jul;32(7):1349-57. doi: 10.1016/0042-6989(92)90227-a.
The spatial analysis of a target may be strongly degraded by the simultaneous presentation of nearby pattern elements. The present study investigated the shape and extent of the region of interaction as a function of retinal location. The stimuli consisted of 3 collinear [symbol: see text] s which were randomly oriented up ([symbol: see text]) or down ([symbol: see text]). The task was to discriminate the orientation of the middle [symbol: see text]. The retinal locations studied were at 0, 2.5, 5 and 10 degrees, on the lower vertical meridian and on the nasal halves of both the horizontal and the 45 degrees diagonal visual field meridians. The extent of the interaction region was defined as the separation between the midpoint of two adjacent [symbol: see text] s that resulted in 75% correct discrimination. The shape of the interaction region was determined by using several orientations (horizontal, vertical, left diagonal and right diagonal) for the virtual line joining the 3. [symbol: see text] s. Our results show that the size of the interaction regions varies linearly with eccentricity as does the size of a just resolved individual [symbol: see text]. However, the size of the interaction region varies much more rapidly than does the resolution threshold for an individual [symbol: see text]. The spatial interaction zones appear to be elongated radially, so that they have an elliptical shape. The size of the major axis is about 2-3 times the size of the minor axis. The major axis is along the meridian through the central visual field (i.e. it is oriented radially) while the minor axis is oriented tangentially (i.e. isoeccentrically).
目标的空间分析可能会因同时呈现附近的图案元素而严重退化。本研究调查了相互作用区域的形状和范围作为视网膜位置的函数。刺激由3个共线的[符号：见原文]组成，它们随机向上（[符号：见原文]）或向下（[符号：见原文]）定向。任务是辨别中间[符号：见原文]的方向。所研究的视网膜位置在0、2.5、5和10度处，位于下垂直子午线以及水平和45度对角视野子午线的鼻侧半部。相互作用区域的范围定义为两个相邻[符号：见原文]的中点之间的间距，该间距导致75%的正确辨别率。通过使用连接3个[符号：见原文]的虚拟线的几种方向（水平、垂直、左对角线和右对角线）来确定相互作用区域的形状。我们的结果表明，相互作用区域的大小随离心率呈线性变化，单个[符号：见原文]的分辨大小也是如此。然而，相互作用区域的大小变化比单个[符号：见原文]的分辨阈值变化快得多。空间相互作用区域似乎呈放射状拉长，因此呈椭圆形。长轴的大小约为短轴大小的2至3倍。长轴沿着穿过中央视野的子午线（即呈放射状定向），而短轴呈切线方向（即等离心率方向）定向。
