Spatial and Object-Based Attention Modulates Broadband High-Frequency Responses across the Human Visual Cortical Hierarchy
Spatial and Object-Based Attention Modulates Broadband High-Frequency Responses across the Human Visual Cortical Hierarchy
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DOI：
10.1523/jneurosci.3181-12.2013
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发表时间：
2013-01-16
影响因子：
5.3
通讯作者：
Malach, Rafael
中科院分区：
文献类型：
--
作者：
Davidesco, Ido;Harel, Michal;Malach, Rafael
视觉注意文献中令人困惑的一个方面是电生理和功能磁共振成像结果之间的差异：功能磁共振成像研究揭示了早期视觉区域强烈的注意调制，而单单元和局部场电位研究得出了不同的结果。此外，尚不清楚空间注意效应从早期视觉区域扩展到高阶视觉区域的程度。在这里，我们利用癫痫患者的皮质电图记录来解决这些问题。患者执行的任务允许同时操作空间和基于物体的注意力。他们被呈现给复合刺激，包括一个小物体（脸或房子）叠加在一个大物体上，并在不同的块中，被指示关注其中一个物体。我们发现宽带高频（30 - 90hz）功率持续增加，但视觉诱发电位没有增加，这与空间注意有关，从V1/V2开始，持续到整个视觉层次。注意调制的强度与每个电极的空间选择性及其与枕极的距离有关。有趣的是，注意调制的潜伏期在视觉层次上有显著的下降。此外，放置在高阶视觉区域（如梭状回）的电极显示了空间和基于物体的注意力的效果。总的来说，我们的研究结果有助于调和以前观察到的功能磁共振成像和电生理学之间的差异。他们还暗示，空间注意效应可以在早期和高阶视觉皮层区域发现，与它们的刺激调谐特性并行。
One of the puzzling aspects in the visual attention literature is the discrepancy between electrophysiological and fMRI findings: whereas fMRI studies reveal strong attentional modulation in the earliest visual areas, single-unit and local field potential studies yielded mixed results. In addition, it is not clear to what extent spatial attention effects extend from early to high-order visual areas. Here we addressed these issues using electrocorticography recordings in epileptic patients. The patients performed a task that allowed simultaneous manipulation of both spatial and object-based attention. They were presented with composite stimuli, consisting of a small object (face or house) superimposed on a large one, and in separate blocks, were instructed to attend one of the objects. We found a consistent increase in broadband high-frequency (30 - 90 Hz) power, but not in visual evoked potentials, associated with spatial attention starting with V1/V2 and continuing throughout the visual hierarchy. The magnitude of the attentional modulation was correlated with the spatial selectivity of each electrode and its distance from the occipital pole. Interestingly, the latency of the attentional modulation showed a significant decrease along the visual hierarchy. In addition, electrodes placed over high-order visual areas (e. g., fusiform gyrus) showed both effects of spatial and object-based attention. Overall, our results help to reconcile previous observations of discrepancy between fMRI and electrophysiology. They also imply that spatial attention effects can be found both in early and high-order visual cortical areas, in parallel with their stimulus tuning properties.