Beck Valerie M, Vickery Timothy J
Department of Psychological and Brain Sciences, University of Delaware, USA.
Department of Psychological and Brain Sciences, University of Delaware, USA.
Cortex. 2020 Jan;122:159-169. doi: 10.1016/j.cortex.2018.09.017. Epub 2018 Oct 4.
Evidence from attentional and oculomotor capture, contingent capture, and other paradigms suggests that mechanisms supporting human visual working memory (VWM) and visual attention are intertwined. Features held in VWM bias guidance toward matching items even when those features are task irrelevant. However, the neural basis of this interaction is underspecified. Prior examinations using fMRI have primarily relied on coarse comparisons across experimental conditions that produce varying amounts of capture. To examine the neural dynamics of attentional capture on a trial-by-trial basis, we applied an oculomotor paradigm that produced discrete measures of capture. On each trial, subjects were shown a memory item, followed by a blank retention interval, then a saccade target that appeared to the left or right. On some trials, an irrelevant distractor appeared above or below fixation. Once the saccade target was fixated, subjects completed a forced-choice memory test. Critically, either the target or distractor could match the feature held in VWM. Although task irrelevant, this manipulation produced differences in behavior: participants were more likely to saccade first to an irrelevant VWM-matching distractor compared with a non-matching distractor - providing a discrete measure of capture. We replicated this finding while recording eye movements and scanning participants' brains using fMRI. To examine the neural basis of oculomotor capture, we separately modeled the retention interval for capture and non-capture trials within the distractor-match condition. We found that frontal activity, including anterior cingulate cortex and superior frontal gyrus regions, differentially predicted subsequent oculomotor capture by a memory-matching distractor. Other regions previously implicated as involved in attentional capture by VWM-matching items showed no differential activity across capture and non-capture trials, even at a liberal threshold. Our findings demonstrate the power of trial-by-trial analyses of oculomotor capture as a means to examine the underlying relationship between VWM and attentional guidance systems.
来自注意力和眼动捕捉、偶然捕捉及其他范式的证据表明，支持人类视觉工作记忆（VWM）和视觉注意力的机制相互交织。即使这些特征与任务无关，VWM中保持的特征也会使注意力偏向于匹配项。然而，这种相互作用的神经基础尚不清楚。先前使用功能磁共振成像（fMRI）的研究主要依赖于对产生不同程度捕捉的实验条件进行粗略比较。为了逐次试验地研究注意力捕捉的神经动力学，我们应用了一种眼动范式，该范式产生了捕捉的离散测量值。在每次试验中，向受试者展示一个记忆项，随后是一个空白的保持间隔，然后是一个出现在左侧或右侧的扫视目标。在一些试验中，一个无关的干扰物出现在注视点上方或下方。一旦扫视目标被注视，受试者完成一个强制选择记忆测试。关键的是，目标或干扰物都可能与VWM中保持的特征相匹配。尽管与任务无关，但这种操作产生了行为上的差异：与不匹配的干扰物相比，参与者更有可能首先扫视到与VWM匹配的无关干扰物——这提供了一种捕捉的离散测量方法。我们在记录眼动并使用fMRI扫描参与者大脑的同时重复了这一发现。为了研究眼动捕捉的神经基础，我们在干扰物匹配条件下分别对捕捉试验和非捕捉试验的保持间隔进行建模。我们发现，额叶活动，包括前扣带回皮层和额上回区域，对记忆匹配干扰物随后的眼动捕捉有不同的预测作用。先前被认为与VWM匹配项引起的注意力捕捉有关的其他区域，在捕捉试验和非捕捉试验中没有显示出差异活动，即使在宽松的阈值下也是如此。我们的研究结果证明了逐次试验分析眼动捕捉作为一种检查VWM和注意力引导系统之间潜在关系的手段的作用。
