Spatial covert attention increases contrast sensitivity across the CSF: support for signal enhancement
Spatial covert attention increases contrast sensitivity across the CSF: support for signal enhancement
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DOI：
10.1016/s0042-6989(00)00024-9
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发表时间：
2000-01-01
期刊：
影响因子：
1.8
通讯作者：
Eckstein, M
中科院分区：
文献类型：
--
作者：
Carrasco, M;Penpeci-Talgar, C;Eckstein, M
这项研究首次报告了当在没有局部后掩模的情况下单独呈现目标时，空间隐蔽注意对大范围空间频率下的对比敏感度的好处。我们使用外围预提示（指示目标位置的小圆圈）来探索隐蔽空间注意对对比敏感度的影响，通过方向辨别（实验 1-4）、检测（实验 2 和 3）和定位（实验 3）任务来评估。在所有四个实验中，目标（空间频率范围从 0.5 到 10 cpd 的 Gabor 斑块）单独出现在与固定等距的八个可能位置之一。尽管我们消除了已知有助于外部降噪解释注意力的变量（干扰因素、全局掩模、局部掩模和位置不确定性），但外周线索试验的对比敏感度始终高于中性线索试验。当观察者看到垂直和水平 Gabor 补丁时，外部降噪信号检测模型在区分任务中发挥了提示作用（实验 1）。然而，当位置不确定性通过以下方式降低时，这种模型无法解释这种好处： (a) 提高整体性能水平（实验 2）； (b) 增加刺激对比度，以实现对稍微倾斜的阈上刺激的精细辨别（实验 3）； (c) 呈现局部后掩模（实验 4）。鉴于注意力获益是在排除外部降噪模型预测的所有变量的条件下发生的，这些结果支持注意力的信号增强模型。 (C) 2000 Elsevier Science Ltd. 保留所有权利。
This study is the first to report the benefits of spatial covert attention on contrast sensitivity in a wide range of spatial frequencies when a target alone was presented in the absence of a local post-mask. We used a peripheral precue (a small circle indicating the target location) to explore the effects of covert spatial attention on contrast sensitivity as assessed by orientation discrimination (Experiments 1-4), detection (Experiments 2 and 3) and localization (Experiment 3) tasks. In all four experiments the target (a Gabor patch ranging in spatial frequency from 0.5 to 10 cpd) was presented alone in one of eight possible locations equidistant from fixation. Contrast sensitivity was consistently higher for peripherally- than for neutrally-cued trials, even though we eliminated variables (distracters, global masks, local masks, and location uncertainty) that are known to contribute to an external noise reduction explanation of attention. When observers were presented with vertical and horizontal Gabor patches an external noise reduction signal detection model accounted for the cueing benefit in a discrimination task (Experiment 1). However, such a model could not account for this benefit when location uncertainty was reduced, either by: (a) Increasing overall performance level (Experiment 2); (b) increasing stimulus contrast to enable fine discriminations of slightly tilted suprathreshold stimuli (Experiment 3); and (c) presenting a local post-mask (Experiment 4). Given that attentional benefits occurred under conditions that exclude all variables predicted by the external noise reduction model, these results support the signal enhancement model of attention. (C) 2000 Elsevier Science Ltd. All rights reserved.