Institute of Cognitive Neuroscience, University College, London, UK.
Cereb Cortex. 2011 Mar;21(3):659-65. doi: 10.1093/cercor/bhq139. Epub 2010 Aug 9.
When stimuli compete for sensory processing and response selection, coherent goal-guided behavior requires cognitive control so that task-relevant "targets" rather than irrelevant distractors are selected. It has been shown that reduced cognitive control under high working memory load increases distractor competition for selection. It remains unknown, though, whether cognitive control by working memory has an effect on the earliest levels of sensory processing in primary visual cortex. The present study addressed this question by having subjects perform a selective attention task involving classification of meaningful target objects while also ignoring congruent and incongruent distractor images. The level of cognitive control over distractor competition was varied through a concurrent working memory task of either low (1 digit) or high (6 digits) load. Functional magnetic resonance imaging revealed greater distractor competition effects not only on behavior but also on the sensory correlates in primary visual cortex (areas V1-V2) in conditions of high (vs. low) working memory load. In addition, high working memory load resulted in increased congruency-related functional connectivity between anterior cingulate cortex and V1. These results are the first to establish the neural correlates of distractor competition effects in primary visual cortex and the critical role of working memory in their cognitive control.
当刺激竞争感官处理和反应选择时，连贯的目标导向行为需要认知控制，以便选择与任务相关的“目标”，而不是无关的干扰物。已经表明，在高工作记忆负载下，认知控制的减少会增加干扰物对选择的竞争。然而，工作记忆的认知控制是否对初级视觉皮层的早期感觉处理水平有影响仍不清楚。本研究通过让受试者执行一个选择性注意任务来解决这个问题，该任务涉及对有意义的目标物体进行分类，同时忽略一致和不一致的干扰图像。通过同时进行低（1 位数字）或高（6 位数字）负载的工作记忆任务来改变对干扰物竞争的认知控制水平。功能磁共振成像显示，在高（与低）工作记忆负载条件下，干扰竞争效应不仅在行为上，而且在初级视觉皮层（V1-V2 区）的感觉相关物上也更大。此外，高工作记忆负载导致前扣带皮层和 V1 之间的一致性相关功能连接增加。这些结果首次确立了初级视觉皮层中干扰竞争效应的神经相关性，以及工作记忆在其认知控制中的关键作用。
