Wildegger T, van Ede F, Woolrich M, Gillebert C R, Nobre A C
Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
Oxford Centre for Human Brain Activity, University of Oxford, Oxford, United Kingdom; and.
J Neurophysiol. 2017 Mar 1;117(3):1385-1394. doi: 10.1152/jn.00856.2016. Epub 2017 Jan 11.
Preparatory modulations of cortical α-band oscillations are a reliable index of the voluntary allocation of covert spatial attention. It is currently unclear whether attentional cues containing information about a target's identity (such as its visual orientation), in addition to its location, might additionally shape preparatory α modulations. Here, we explore this question by directly comparing spatial and feature-based attention in the same visual detection task while recording brain activity using magnetoencephalography (MEG). At the behavioral level, preparatory feature-based and spatial attention cues both improved performance and did so independently of each other. Using MEG, we replicated robust α lateralization following spatial cues: in preparation for a visual target, α power decreased contralaterally and increased ipsilaterally to the attended location. Critically, however, preparatory α lateralization was not significantly modulated by predictions regarding target identity, as carried via the behaviorally effective feature-based attention cues. Furthermore, nonlateralized α power during the cue-target interval did not differentiate between uninformative cues and cues carrying feature-based predictions either. Based on these results we propose that preparatory α modulations play a role in the gating of information between spatially segregated cortical regions and are therefore particularly well suited for spatial gating of information. The present work clarifies if and how human brain oscillations in the α-band support multiple types of anticipatory attention. Using magnetoencephalography, we show that posterior α-band oscillations are modulated by predictions regarding the spatial location of an upcoming visual target, but not by feature-based predictions regarding its identity, despite robust behavioral benefits. This provides novel insights into the functional role of preparatory α mechanisms and suggests a limited specificity with which they may operate.
皮层α波段振荡的预备调制是隐蔽空间注意力自愿分配的可靠指标。目前尚不清楚，除了目标位置信息之外，包含目标身份信息（如视觉方向）的注意力线索是否还会额外影响预备α调制。在这里，我们通过在同一视觉检测任务中直接比较基于空间和基于特征的注意力，并使用脑磁图（MEG）记录大脑活动，来探讨这个问题。在行为层面，基于特征的预备注意力线索和空间注意力线索都提高了表现，而且二者相互独立。使用MEG，我们复制了空间线索后强大的α偏侧化：为准备视觉目标，α功率在对侧降低，在同侧增加到被关注的位置。然而，关键的是，预备α偏侧化并没有被通过行为上有效的基于特征的注意力线索所携带的关于目标身份的预测显著调制。此外，在线索-目标间隔期间的非偏侧化α功率也没有区分无信息线索和携带基于特征预测的线索。基于这些结果，我们提出预备α调制在空间上分离的皮层区域之间的信息门控中起作用，因此特别适合于信息的空间门控。目前的工作阐明了α波段的人类脑振荡是否以及如何支持多种类型的预期注意力。使用脑磁图，我们表明后部α波段振荡受到关于即将到来的视觉目标空间位置的预测的调制，但不受关于其身份的基于特征的预测的调制，尽管在行为上有显著益处。这为预备α机制的功能作用提供了新的见解，并表明它们可能运作的特异性有限。
