Global Facilitation of Attended Features Is Obligatory and Restricts Divided Attention
Global Facilitation of Attended Features Is Obligatory and Restricts Divided Attention
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DOI：
10.1523/jneurosci.1913-13.2013
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发表时间：
2013-11-13
影响因子：
5.3
通讯作者：
Mueller, Matthias M.
中科院分区：
文献类型：
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作者：
Andersen, Soren K.;Hillyard, Steven A.;Mueller, Matthias M.
在许多常见的情况下，例如驾驶汽车，同时参加不同地点的事件是有利的（例如，前面的汽车，旁边的行人）。虽然空间注意力可以在不同的位置之间有效地分配，但研究对非空间特征的注意力的研究经常报告了一种“全局效应”，即具有被关注特征的事物可能在整个视野中被优先处理。这些发现表明，空间注意力和基于特征的注意力有时可能是直接对立的：如果特征注意力是空间全局的，那么空间分裂的注意力焦点就不可能真正独立，从而平等地影响所有焦点。在两个实验中，人类观察者同时注意左右两个视野中呈现的不同颜色的圆点重叠区域中的一个。当同一颜色或两种不同颜色同时被注视时，能准确地检测出异常目标，被注视点引发的视觉皮层电位增强。然而，当一侧被注意的颜色与另一侧被忽略的颜色相匹配时，皮层电位的注意调制被消除。这种特征选择性的丧失可以归因于对未参与项目的增强处理，这些项目与相反领域中参与项目的颜色相同。因此，虽然同时注意两种不同的颜色是可能的，但这种能力从根本上受到早期视觉皮质区域的空间全局特征增强的限制，这是强制性的，即使在与任务要求明显冲突时也会持续存在。
In many common situations such as driving an automobile it is advantageous to attend concurrently to events at different locations (e. g., the car in front, the pedestrian to the side). While spatial attention can be divided effectively between separate locations, studies investigating attention to nonspatial features have often reported a "global effect", whereby items having the attended feature may be preferentially processed throughout the entire visual field. These findings suggest that spatial and feature-based attention may at times act in direct opposition: spatially divided foci of attention cannot be truly independent if feature attention is spatially global and thereby affects all foci equally.In two experiments, human observers attended concurrently to one of two overlapping fields of dots of different colors presented in both the left and right visual fields. When the same color or two different colors were attended on the two sides, deviant targets were detected accurately, and visual-cortical potentials elicited by attended dots were enhanced. However, when the attended color on one side matched the ignored color on the opposite side, attentional modulation of cortical potentials was abolished. This loss of feature selectivity could be attributed to enhanced processing of unattended items that shared the color of the attended items in the opposite field. Thus, while it is possible to attend to two different colors at the same time, this ability is fundamentally constrained by spatially global feature enhancement in early visual-cortical areas, which is obligatory and persists even when it explicitly conflicts with task demands.