Determinants of Global Color-Based Selection in Human Visual Cortex
Determinants of Global Color-Based Selection in Human Visual Cortex
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DOI：
10.1093/cercor/bhu078
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发表时间：
2015-09-01
期刊：
影响因子：
3.7
通讯作者：
Hopf, Jens-Max
中科院分区：
文献类型：
--
作者：
Bartsch, Mandy V.;Boehler, Carsten N.;Hopf, Jens-Max
特征关注以空间全局的方式操作，关注的特征值被优先选择在关注的焦点之外。全球功能关注的帐户强调功能竞争作为一个决定性因素。在这里，我们使用人类的脑磁图记录来测试竞争是否对全局特征选择的出现至关重要。受试者在一个视野（VF）中进行颜色/形状辨别任务，而在另一个无人值守的VF中呈现不相关的颜色探针。通过分析对探针的响应作为探针的颜色是否是目标定义颜色的函数来评估颜色注意力的全局效应。我们发现，全球的颜色选择涉及一系列的调制在纹外皮层，在较高层地区（枕叶外侧复合体）的初始阶段，随后在较低层视网膜区域（V3/V4）的后期阶段。重要的是，这些调制出现在注意力焦点的颜色竞争和不竞争。此外，调制的早期部分出现了与任务相关的颜色，甚至不存在于注意力的焦点。然而，所有的调制，消除在简单的发病检测的彩色目标。这些结果表明，全球基于颜色的注意依赖于目标的歧视独立的特征竞争的关注焦点。
Feature attention operates in a spatially global way, with attended feature values being prioritized for selection outside the focus of attention. Accounts of global feature attention have emphasized feature competition as a determining factor. Here, we use magnetoencephalographic recordings in humans to test whether competition is critical for global feature selection to arise. Subjects performed a color/shape discrimination task in one visual field (VF), while irrelevant color probes were presented in the other unattended VF. Global effects of color attention were assessed by analyzing the response to the probe as a function of whether or not the probe's color was a target-defining color. We find that global color selection involves a sequence of modulations in extrastriate cortex, with an initial phase in higher tier areas (lateral occipital complex) followed by a later phase in lower tier retinotopic areas (V3/V4). Importantly, these modulations appeared with and without color competition in the focus of attention. Moreover, early parts of the modulation emerged for a task-relevant color not even present in the focus of attention. All modulations, however, were eliminated during simple onset-detection of the colored target. These results indicate that global color-based attention depends on target discrimination independent of feature competition in the focus of attention.