Mussap A J, Levi D M
College of Optometry, University of Houston, TX 77204-6052, USA.
Vision Res. 1996 Aug;36(16):2459-73. doi: 10.1016/0042-6989(95)00306-1.
Models of vernier acuity based on the differential response of oriented filters receive support from the finding that vernier threshold elevation peaks for grating mask orientations which are slightly different from the orientation of the vernier bars. We replicate this effect using long, abutting vernier bars, and masks which possess gaps up to 22.5' wide (Experiments 1 and 3); a surprising result considering that vernier acuity improves little for bars longer than 10'. To account for this we suggest the involvement of elongated mechanisms (referred to as collators or collectors) that "integrate" responses of numerous smaller filters along the axis of their common orientation. The collator model explains patterns of threshold elevation obtained with a variety of mask-vernier configurations. In particular, the model predicts that masks located midway between separated vernier bars will interfere with integrative processes occurring over the entire region encompassing both bars (Experiment 2). In confirmation of this prediction we find that centrally placed masks produce significant orientation-specific threshold elevation. In suggesting a contribution to vernier acuity from integrative mechanisms, our results, along with others, emphasize the importance of global processes in vernier acuity.
对于与游标条方向略有不同的光栅掩膜方向，游标阈值升高达到峰值。我们使用长的、相邻的游标条以及宽度达22.5'的间隙掩膜来复制这种效应（实验1和3）；考虑到对于长度超过10'的条，游标视力改善很小，这是一个令人惊讶的结果。为了解释这一点，我们提出存在细长机制（称为校对器或收集器），其沿着共同方向的轴“整合”众多较小滤波器的响应。校对器模型解释了通过各种掩膜 - 游标配置获得的阈值升高模式。特别是，该模型预测位于分开的游标条中间的掩膜会干扰在包含两条的整个区域上发生的整合过程（实验2）。为证实这一预测，我们发现置于中央的掩膜会产生显著的方向特异性阈值升高。在表明整合机制对游标视力有贡献时，我们的结果以及其他结果强调了全局过程在游标视力中的重要性。
