Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
PLoS One. 2009 Oct 29;4(10):e7613. doi: 10.1371/journal.pone.0007613.
Previous research has examined our ability to attend selectively to particular features of perceptual objects, as well as our ability to switch from attending to one type of feature to another. This is usually done in the context of anticipatory attentional-set control, comparing the neural mechanisms involved as participants prepare to attend to the same stimulus feature as on the previous trial ("task-stay" trials) with those required as participants prepare to attend to a different stimulus feature to that previously attended ("task-switch" trials). We wanted to establish how participants maintain or switch attentional set retrospectively, as they attend to features of objects held in visual short-term memory (VSTM). We found that switching, relative to maintaining attentional set retrospectively, was associated with a performance cost, which can be reduced over time. This control process was mirrored by a large parietal and frontal amplitude difference in the event-related brain potentials (ERPs) and significant differences in global field power (GFP) between switch and stay trials. However, when taking into account the switch/stay GFP differences, thereby controlling for this difference in amplitude, we could not distinguish these trial types topographically. By contrast, we found clear topographic differences between preparing an anticipatory feature-based attentional set versus applying it retrospectively within VSTM. These complementary topographical and amplitude analyses suggested that anticipatory and retrospective set control recruited a qualitatively different configuration of underlying neural generators. In contrast, switch/stay differences were largely quantitative, with them differing primarily in terms of amplitude rather than topography.
先前的研究考察了我们选择性地注意感知对象特定特征的能力，以及我们从关注一种特征类型切换到另一种特征类型的能力。这通常是在预期注意设定控制的背景下进行的，比较参与者在准备关注与前一次试验相同的刺激特征（“任务保持”试验）时所涉及的神经机制与参与者在准备关注与以前注意的不同刺激特征（“任务切换”试验）时所涉及的神经机制。我们想确定参与者在视觉短期记忆（VSTM）中注意对象的特征时，如何回顾性地维持或切换注意设定。我们发现，与回顾性地保持注意设定相比，切换与绩效成本相关，这种成本可以随着时间的推移而降低。这种控制过程在事件相关脑电位（ERPs）中表现为顶叶和额叶的振幅差异较大，在开关试验和保持试验之间的全局场功率（GFP）存在显著差异。然而，当考虑到开关/保持 GFP 差异时，即控制了幅度上的差异，我们无法在地形上区分这些试验类型。相比之下，我们发现准备基于预期特征的注意力集与在 VSTM 中回顾性应用之间存在明显的地形差异。这些互补的地形和幅度分析表明，预期和回顾性的设定控制招募了不同性质的潜在神经发生器配置。相比之下，开关/保持差异主要是定量的，它们主要在幅度上而不是地形上存在差异。
