Differential effects of exogenous and endogenous attention on second-order texture contrast sensitivity
Differential effects of exogenous and endogenous attention on second-order texture contrast sensitivity
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DOI：
10.1167/12/8/6
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发表时间：
2012-01-01
影响因子：
1.8
通讯作者：
Carrasco, Marisa
中科院分区：
文献类型：
--
作者：
Barbot, Antoine;Landy, Michael S.;Carrasco, Marisa
视觉系统可以使用丰富多样的轮廓将视觉场景分割成不同的感知连贯区域。然而，成功地分割图像是计算上昂贵的过程。以前，我们已经表明，外源性的注意力，更自动，刺激驱动的空间注意力的组成部分，有助于提取轮廓，通过提高对比敏感度的二阶，纹理定义的模式在出席的位置，而在无人值守的位置，相对于一个中立的条件下，降低敏感度。有趣的是，外源性注意的影响依赖于刺激的二阶空间频率。在旁视位置，注意力增强二阶对比敏感度相对较高，但不是低的二阶空间频率。在本研究中，我们调查是否内源性注意，更多的自愿，概念驱动的空间注意力的组成部分，影响二阶对比敏感度，如果是这样的话，其影响是否是类似的外源性注意。为此，我们比较了外源性和内源性的注意力的敏感性，二阶，方向定义，纹理模式的高或低的二阶空间频率的影响。结果表明，像外源性注意，内源性注意提高二阶对比敏感度在有人值守的位置，并降低它在无人值守的位置。然而，而外源性注意的影响是二阶空间频率内容的函数，内源性注意影响二阶对比敏感度的二阶空间频率内容的独立。这一发现支持了这样的观点，即外源性和内源性注意都可以影响二阶对比敏感度，但内源性注意更灵活，在不同条件下有利于表现。
The visual system can use a rich variety of contours to segment visual scenes into distinct perceptually coherent regions. However, successfully segmenting an image is a computationally expensive process. Previously we have shown that exogenous attention-the more automatic, stimulus-driven component of spatial attention-helps extract contours by enhancing contrast sensitivity for second-order, texture-defined patterns at the attended location, while reducing sensitivity at unattended locations, relative to a neutral condition. Interestingly, the effects of exogenous attention depended on the second-order spatial frequency of the stimulus. At parafoveal locations, attention enhanced second-order contrast sensitivity to relatively high, but not to low second-order spatial frequencies. In the present study we investigated whether endogenous attention-the more voluntary, conceptually-driven component of spatial attention-affects second-order contrast sensitivity, and if so, whether its effects are similar to those of exogenous attention. To that end, we compared the effects of exogenous and endogenous attention on the sensitivity to second-order, orientation-defined, texture patterns of either high or low second-order spatial frequencies. The results show that, like exogenous attention, endogenous attention enhances second-order contrast sensitivity at the attended location and reduces it at unattended locations. However, whereas the effects of exogenous attention are a function of the second-order spatial frequency content, endogenous attention affected second-order contrast sensitivity independent of the second-order spatial frequency content. This finding supports the notion that both exogenous and endogenous attention can affect second-order contrast sensitivity, but that endogenous attention is more flexible, benefitting performance under different conditions.