Delayed effects of attention in visual cortex as measured with fMRI.
Delayed effects of attention in visual cortex as measured with fMRI.
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DOI：
10.1016/j.neuroimage.2011.04.012
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发表时间：
2011-08-01
期刊：
影响因子：
5.7
通讯作者：
Engel, Stephen A.
中科院分区：
文献类型：
--
作者：
Bouvier, Seth E.;Engel, Stephen A.
注意力在多大程度上调节早期视觉区域的神经活动？对初级视觉皮层 (V1) 注意力调节的功能磁共振成像测量显示出很大的影响，而单个单元记录显示的影响要小得多。这种差异表明，功能磁共振成像的注意力测量可能会被夸大，可能是由于与其他过程相关的活动。为了测试功能磁共振成像测量的效果是否确实反映了注意力的增强，我们使用了快速采集协议来确定其时间。受试者在注视的两侧受到两种刺激，并被提示注意其中一个而忽略另一个。有人参与的刺激在 V1 中显示出更大幅度的反应，但相对于无人参与的反应和由于刺激对比度增强而导致的反应增加，这种增加在时间上延迟了大约一秒。这些结果表明，功能磁共振成像对注意力的测量可能主要取决于需要相对较长时间反馈到 V1 的其他过程。我们的结果证明了使用功能磁共振成像响应中可用的精细定时信息的重要性。
To what extent does attention modulate neural activity in early visual areas? fMRI measurements of attentional modulation in primary visual cortex (V1) show large effects, while single unit recordings show much smaller ones. This discrepancy suggests that fMRI measures of attention may be inflated, perhaps by activity related to other processes. To test whether effects measured with fMRI actually reflect attentional enhancement, we used a rapid acquisition protocol to determine their timing. Subjects were presented with two stimuli on either side of fixation and were cued to attend one and ignore the other. Attended stimuli showed a greater magnitude of response in V1, but this increase was delayed, by roughly one second in time, relative to both unattended responses and response increases due to boosting stimulus contrast. These results suggest that fMRI measurements of attention may primarily depend upon other processes that take a relatively long time to feed back to V1. Our results demonstrate the importance of using the fine timing information available in the fMRI response.
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