Beijing Key Laboratory of Learning and Cognition and Department of Psychology, Capital Normal University, Beijing 100048, China; Department of Psychology, LMU München, D-80802 München, Germany; Center for Brain and Cognition Sciences and Department of Psychology, Peking University, Beijing 100871, China.
Neuroscience. 2013 Oct 10;250:372-80. doi: 10.1016/j.neuroscience.2013.07.025. Epub 2013 Jul 20.
The neural correlates of perceptual load induced attentional selection were investigated in an functional magnetic resonance imaging (fMRI) experiment in which attentional selection was manipulated through the variation of perceptual load in target search. Participants searched for a vertically or horizontally oriented bar among heterogeneously (the high load condition) or homogeneously (the low load condition) oriented distractor bars in the central display, which was flanked by a vertical or horizontal bar presented at the left or the right periphery. The search reaction times were longer when the central display was of high load than of low load, and were longer when the flanker was incongruent than congruent with the target. Importantly, the flanker congruency effect was manifested only in the low load condition, not in the high load condition, indicating that the perceptual load in target search determined whether the task-irrelevant flanker was processed. Imaging analyses revealed a set of fronto-parietal regions having higher activations in the high than in the low load condition. Anterior cingulate cortex (ACC) was more activated for the incongruent than for the congruent trials. Moreover, ACC and bilateral anterior insula were sensitive to the interaction between perceptual load and flanker congruency such that the activation differences between the incongruent and congruent conditions were significant in the low, but not in the high load condition. These results are consistent with the claim that ACC and bilateral anterior insula may exert executive control by selectively biasing processing in favor of task-relevant information and this biasing depends on the resources currently available to the control system.
在一项功能磁共振成像（fMRI）实验中研究了知觉负载诱导的注意选择的神经相关物，其中通过目标搜索中知觉负载的变化来操纵注意选择。参与者在中央显示器中搜索垂直或水平定向的棒，中央显示器中存在异质（高负载条件）或同质（低负载条件）定向的干扰棒，其两侧分别在左侧或右侧显示垂直或水平棒。当中央显示器的负载较高时，搜索反应时间会更长，当侧翼与目标不一致时，搜索反应时间会更长。重要的是，仅在低负载条件下表现出侧翼一致性效应，而在高负载条件下则没有，这表明目标搜索中的知觉负载决定了任务无关的侧翼是否被处理。成像分析显示了一组额顶叶区域，在高负载条件下比在低负载条件下具有更高的激活。前扣带皮层（ACC）对不一致的试验比一致的试验更活跃。此外，ACC 和双侧前岛叶对知觉负载和侧翼一致性之间的相互作用敏感，使得在低负载条件下，而不是在高负载条件下，不一致和一致条件之间的激活差异显著。这些结果与 ACC 和双侧前岛叶通过选择性地偏向有利于任务相关信息的处理来施加执行控制的说法一致，这种偏向取决于控制系统当前可用的资源。
