Exogenous attention enhances 2nd-order contrast sensitivity.
Exogenous attention enhances 2nd-order contrast sensitivity.
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DOI：
10.1016/j.visres.2011.02.022
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发表时间：
2011-05-11
期刊：
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
自然场景包含丰富多样的轮廓，视觉系统提取这些轮廓，将视网膜图像分离为感知上连贯的区域。相对于中性的注意分配，隐蔽空间注意有助于通过增强一阶、亮度定义模式在有人在场位置的对比灵敏度，同时降低无人在场位置的灵敏度来提取轮廓。然而，人类对纹理的空间变化等二阶模式也很敏感，这些模式在自然场景中占主导地位，无法被线性机制检测到。我们评估外源性注意——空间注意的非自愿和短暂捕获——是否以及如何影响对二阶纹理定义模式敏感的通道的对比敏感性。使用二阶、纹理定义的刺激，我们证明了相对于中性条件，外生注意增加了被注意位置的二阶对比灵敏度，而在无人注意位置则降低了它。通过控制一阶和二阶空间频率，我们发现注意力的影响既取决于刺激的二阶空间频率，也取决于观察者在目标位置的二阶空间分辨率。在准中央凹位置，注意力增强了对高阶空间频率的二阶对比灵敏度，但对低阶空间频率没有增强；在外围位置，注意力也增强了对低二阶空间频率的灵敏度。对照实验排除了这种可能性，即这些影响可能是由于在视觉处理的第一阶阶段对比度灵敏度的增加。因此，外源性注意影响二级对比敏感性在有人参与和无人参与的位置。
Natural scenes contain a rich variety of contours that the visual system extracts to segregrate the retinal image into perceptually coherent regions. Covert spatial attention helps extract contours by enhancing contrast sensitivity for 1st-order, luminance-defined patterns at attended locations, while reducing sensitivity at unattended locations, relative to neutral attention allocation. However, humans are also sensitive to 2nd-order patterns such as spatial variations of texture, which are predominant in natural scenes and cannot be detected by linear mechanisms. We assess whether and how exogenous attention—the involuntary and transient capture of spatial attention—affects the contrast sensitivity of channels sensitive to 2nd-order, texture-defined patterns. Using 2nd-order, texture-defined stimuli, we demonstrate that exogenous attention increases 2nd-order contrast sensitivity at the attended location, while decreasing it at unattended locations, relative to a neutral condition. By manipulating both 1st- and 2nd-order spatial frequency, we find that the effects of attention depend both on 2nd-order spatial frequency of the stimulus and the observer’s 2nd-order spatial resolution at the target location. At parafoveal locations, attention enhances 2nd-order contrast sensitivity to high, but not to low 2nd-order spatial frequencies; at peripheral locations attention also enhances sensitivity to low 2nd-order spatial frequencies. Control experiments rule out the possibility that these effects might be due to an increase in contrast sensitivity at the 1st-order stage of visual processing. Thus, exogenous attention affects 2nd-order contrast sensitivity at both attended and unattended locations.
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影响因子：
1.8
作者：
Carrasco, Marisa;Williams, Patrick E;Yeshurun, Yaffa
通讯作者：
Yeshurun, Yaffa
影响因子：
1.8
作者：
Balz, GW;Hock, HS
通讯作者：
Hock, HS
影响因子：
1.8
作者：
Appelbaum, Lawrence G.;Norcia, Anthony M.
通讯作者：
Norcia, Anthony M.
影响因子：
1.8
作者：
Allen, HA;Ledgeway, T
通讯作者：
Ledgeway, T
DOI：
10.1080/14640749108400960
发表时间：
1991-11-01
期刊：
QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY SECTION A-HUMAN EXPERIMENTAL PSYCHOLOGY
影响因子：
--
作者：
CHEAL, ML;LYON, DR
通讯作者：
LYON, DR