The role of alpha-band oscillations in feature-based selective attention.

当隐蔽地注意到行为相关信息预计会发生的空间区域时，对出现在这些位置的视觉刺激的处理得到增强。相反，如果一个空间区域被认为是分散注意力的事件发生地，那么对那里发生的刺激的处理就会减弱。后一种抑制过程通过脑电图中α波段（8- 15 Hz）振荡功率的视网膜定位特异性增加来反映。基于动物中类似振荡的细胞生理学，已经提出α可能作为功能性门控机制。重要的是，已经发现的神经区域网络有助于产生这些节律，包括额叶、顶叶和枕叶视觉区域以及丘脑核，这些区域与几种有影响力的注意力操作理论所涉及的区域相同。需要进一步表征的α-波段措施，以确定在何种程度上是副现象的注意力部署机制，或更确切地说，内源性注意力机制本身。迄今为止，选择性注意的α波段测量仅针对空间注意进行了表征。然而，注意力也可以部署到非空间视觉特征，如颜色或运动参数，促进后续刺激与关注的功能，独立于其空间位置的处理。 该项目的目标是通过在纯粹基于特征的注意力任务中测试其时空特性来进一步表征α波段注意力测量。 为此，一个经典的视觉空间选择性注意任务将被转换成一个纯粹的特征域。一个象征性的提示将告知参与者即将到来的刺激的任务相关特征，而大脑电活动则在头皮上记录下来。提示和命令性刺激将被一个没有刺激发生的间隔分开，在此期间的大脑活动反映了内部的准备注意过程。通过改变参数的线索（如其信息量）和必要的刺激（如其持续时间或连贯性）的情况下，将创建不同的注意力集是有利的，允许评估的程度和限制的α-波段功率增加作为一种机制，在有偏见的竞争模型的抑制。

When covertly attending to regions of space where behaviorally relevant information is expected to occur, processing of visual stimuli appearing at those locations is enhanced. Conversely, if a region of space is expected to be a locus of distracting events, processing of stimuli occurring there is attenuated. This latter suppressive process is reflected by retinotopically specific increases of alpha-band (8-15Hz) oscillatory power in the electroencephalogram. Based on the cellular physiology of similar oscillations in animals, it has been proposed that alpha might serve as a functional gating mechanism. Importantly, the network of neural areas that have been found to contribute to the generation of these rhythms, which include frontal, parietal and occipital visual areas and thalamic nuclei are the same areas implicated in several influential theories of attentional operations. Further characterization of the alpha-band measure is needed to determine the extent to which it is epiphenomenal to attentional deployment mechanisms, or rather an endogenous attentional mechanism per se. To date, the alpha-band measure of selective attention has only been characterized with respect to spatial attention. However, attention can also be deployed to non-spatial visual features, such as color or motion parameters, facilitating the processing of subsequent stimuli with the attended feature, independently of its spatial location. The goal of this project is to further characterize the alpha-band attentional measure by testing its spatiotemporal properties in a purely feature-based attention task. To this end, a classic visual spatial selective attention task will be transformed into a purely featural domain. A symbolic cue will inform participants about a task-relevant feature of an upcoming stimulus, while electrical brain activity is recorded at the scalp. The cue and imperative stimuli will be separated by an interval during which no stimulation occurs, the brain activity during which reflects internal preparatory attentional processes. By varying parameters of the cue (such as its informativeness) and imperative stimuli (such as its duration or coherence) contexts will be created for which different attentional sets are advantageous, allowing the assessment of the extent and limits of alpha-band power increases as a mechanism for suppression in biased competition models.