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

当隐蔽地关注预期会发生行为相关信息的空间区域时，对出现在这些位置的视觉刺激的处理会得到加强。相反，如果一个空间区域被认为是分散注意力的事件的发生地，那么对发生在那里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（8-15Hz）振荡功率的特异性增加来反映。基于动物中类似振荡的细胞生理学，有人提出α可能是一种功能性门控机制。重要的是，已经发现的与这些节律的产生有关的神经区域网络，包括额叶、顶叶和枕叶视觉区以及丘脑核，与几个有影响力的注意力操作理论有关。需要进一步表征α波段测量，以确定它在多大程度上是注意部署机制的副现象，或者更确切地说，是一种内源性注意机制本身。迄今为止，选择性注意的α波段测量仅在空间注意方面具有特征。然而，注意力也可以被部署到非空间视觉特征上，如颜色或运动参数，从而促进后续刺激的处理，而不受其空间位置的影响。

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.