Covert spatial attention is thought to facilitate the maintenance of locations in working memory, and EEG alpha-band activity (8 - 12 Hz) is proposed to track the focus of covert attention. Recent work has shown that multivariate patterns of alpha-band activity track the polar angle of remembered locations relative to fixation. However, a defining feature of covert spatial attention is that it facilitates processing in a specific region of the visual field, and prior work has not determined whether patterns of alpha-band activity track the two-dimensional coordinates of remembered stimuli within a visual hemifield or are instead maximally sensitive to the polar angle of remembered locations around fixation. Here we used a lateralized spatial estimation task, in which observers remembered the location of one or two target dots presented to one side of fixation, to test this question. By applying a linear discriminant classifier to the topography of alpha-band activity, we found that we were able to decode the location of remembered stimuli. Critically, model comparison revealed that the pattern of classifier choices observed across remembered positions was best explained by a model assuming that alpha-band activity tracks the 2d-coordinates of remembered locations rather than a model assuming that alpha-band activity tracks the polar angle of remembered locations relative to fixation. These results support the hypothesis that this alpha-band activity is involved in the spotlight of attention, and arises from mid- to lower-level visual areas involved in maintaining spatial locations in working memory.

中文翻译：

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在空间工作记忆维护期间，Alpha 波段活动跟踪关注的二维聚光灯

隐蔽空间注意力被认为有助于维持工作记忆中的位置，并提出脑电图 α 波段活动 (8 - 12 Hz) 来跟踪隐蔽注意力的焦点。最近的研究表明，α 波段活动的多元模式跟踪记忆位置相对于注视的极角。然而，隐蔽空间注意的一个定义特征是它有助于在视野的特定区域进行处理，而先前的工作尚未确定 alpha 带活动模式是否跟踪视觉半场内记忆刺激的二维坐标或相反，它们对注视周围记忆位置的极角最敏感。在这里，我们使用了横向空间估计任务，其中观察者记住一个或两个目标点的位置出现在注视的一侧，以测试这个问题。通过将线性判别分类器应用于 alpha 波段活动的地形，我们发现我们能够解码记忆刺激的位置。至关重要的是，模型比较表明，在记忆位置上观察到的分类器选择模式最好通过假设 alpha 波段活动跟踪记忆位置的 2d 坐标的模型来解释，而不是假设 alpha 波段活动跟踪极角的模型。记住与注视相关的位置。这些结果支持这样的假设，即这种 alpha 波段活动涉及注意力的聚光灯，并且来自与维持工作记忆中的空间位置有关的中低级视觉区域。