Microsaccade-related brain potentials signal the focus of visuospatial attention
Microsaccade-related brain potentials signal the focus of visuospatial attention
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DOI：
10.1016/j.neuroimage.2014.09.065
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发表时间：
2015-01-01
期刊：
影响因子：
5.7
通讯作者：
Dimigen, Olaf
中科院分区：
文献类型：
--
作者：
Meyberg, Susann;Werkle-Bergner, Markus;Dimigen, Olaf
视觉空间注意的内隐转移传统上被认为是在没有眼动行为的情况下发生的。相比之下，最近的行为研究将注意力线索效应与微扫视的发生联系起来，微扫视是在试图固定时不自觉地执行的小眼球运动。在这里，我们使用了一种新型的电生理标记来探讨注意-微眼跳的关系，微眼跳本身引起的视觉脑活动。通过改变视网膜图像，微扫视频繁地引起整个视觉通路的神经反应，在人类EEG中可作为微扫视相关电位（mSRP）头皮记录。虽然mSRPs包含与传统视觉诱发电位（VEP）相似的信号成分（P1/N1），但尚不清楚它们是否也受到认知的影响。基于VEP在当前有人值守的位置被放大用于视觉输入的既定研究结果，我们预期mSRP也会有选择性增益调制。眼动和脑电图共注册在一个经典的空间提示任务与内源性线索。重复行为发现，早期微眼跳的方向在线索启动后200- 400毫秒偏向线索侧。然而，对于整个提示-目标间隔的微扫视，提示半野对侧的枕部头皮部位的mSRPs系统性增强。这种注意力效应类似于在控制条件下与VEP，并没有相互作用的方向的基础微扫视，这表明mSRPs反映了持续的视觉空间注意力的焦点，它仍然固定在线索的位置，尽管微扫视。微扫视不仅仅是EEG中的伪影源;相反，它们之后是认知调制的脑电位，其可以用作注意力的非侵入性电生理探针。(C)2014 Elsevier Inc. All rights reserved.
Covert shifts of visuospatial attention are traditionally assumed to occur in the absence of oculomotor behavior. In contrast, recent behavioral studies have linked attentional cueing effects to the occurrence of microsaccades, small eye movements executed involuntarily during attempted fixation. Here we used a new type of electrophysiological marker to explore the attention-microsaccade relationship, the visual brain activity evoked by the microsaccade itself. By shifting the retinal image, microsaccades frequently elicit neural responses throughout the visual pathway, scalp-recordable in the human EEG as a microsaccade-related potential (mSRP). Although mSRPs contain similar signal components (P1/N1) as traditional visually-evoked potentials (VEPs), it is unknown whether they are also influenced by cognition. Based on established findings that VEPs are amplified for visual inputs at currently attended locations, we expected a selective gain-modulation also for mSRPs. Eye movements and EEG were coregistered in a classic spatial cueing task with an endogenous cue. Replicating behavioral findings, the direction of early microsaccades 200-400ms after cue onset was biased towards the cued side. However, for microsaccades throughout the cue-target interval, mSRPs were systematically enhanced at occipital scalp sites contralateral to the cued hemifield. This attention effect resembled that in a control condition with VEPs and did not interact with the direction of the underlying microsaccade, suggesting that mSRPs reflect the focus of sustained visuospatial attention, which remains fixed at the cued location, despite microsaccades. Microsaccades are not merely an artifact source in the EEG; instead, they are followed by cognitively modulated brain potentials that can serve as non-intrusive electrophysiological probes of attention. (C) 2014 Elsevier Inc. All rights reserved.