Attention improves encoding of task-relevant features in the human visual cortex.
Attention improves encoding of task-relevant features in the human visual cortex.
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DOI：
10.1523/jneurosci.6153-09.2011
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发表时间：
2011-06-01
期刊：
影响因子：
--
通讯作者：
Tong F
中科院分区：
文献类型：
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作者：
Jehee JF;Brady DK;Tong F
当空间注意力指向特定刺激时，通常在视觉皮层的相应位置观察到活动增加。这种注意力活动的增加是否表明对所关注的刺激中包含的所有特征的处理得到了改善，或者可能是空间注意力选择性地增强了与观察者任务相关的特征？我们使用功能磁共振成像解码方法来测量强度的方向选择性活动模式在人类视觉皮层，而受试者进行方向或对比度的歧视任务，涉及两个横向光栅之一。更大的整体BOLD激活与空间注意，观察到在V1-V4区的两个任务。然而，多变量模式分析表明，方向选择性反应增强注意只有当方向是任务相关的功能，而不是当光栅的对比度必须参加。在第二个实验中，观察者辨别特定横向光栅的方向或颜色。在这里，方向选择性反应增强，在这两个任务，但颜色选择性反应增强，只有当颜色是任务相关的。在这两个实验中，任务特定的功能选择性活动的增强不仅限于参加刺激的位置，而是蔓延到其他位置在视野中，这表明同时参与的全球功能为基础的注意力机制。这些结果表明，注意力可以显着选择性的能力，以提高特定的任务相关的功能，并进一步揭示，在整体BOLD幅度的增加不一定伴随着刺激信息的处理改善。
When spatial attention is directed towards a particular stimulus, increased activity is commonly observed in corresponding locations of the visual cortex. Does this attentional increase in activity indicate improved processing of all features contained within the attended stimulus, or might spatial attention selectively enhance the features relevant to the observer’s task? We used fMRI decoding methods to measure the strength of orientation-selective activity patterns in the human visual cortex while subjects performed either an orientation or contrast discrimination task, involving one of two laterally presented gratings. Greater overall BOLD activation with spatial attention was observed in areas V1-V4 for both tasks. However, multivariate pattern analysis revealed that orientation-selective responses were enhanced by attention only when orientation was the task-relevant feature, and not when the grating’s contrast had to be attended. In a second experiment, observers discriminated the orientation or color of a specific lateral grating. Here, orientation-selective responses were enhanced in both tasks but color-selective responses were enhanced only when color was task-relevant. In both experiments, task-specific enhancement of feature-selective activity was not confined to the attended stimulus location, but instead spread to other locations in the visual field, suggesting the concurrent involvement of a global feature-based attentional mechanism. These results suggest that attention can be remarkably selective in its ability to enhance particular task-relevant features, and further reveal that increases in overall BOLD amplitude are not necessarily accompanied by improved processing of stimulus information.