Causal evidence for frontal involvement in memory target maintenance by posterior brain areas during distracter interference of visual working memory
Causal evidence for frontal involvement in memory target maintenance by posterior brain areas during distracter interference of visual working memory
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DOI：
10.1073/pnas.1106439108
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发表时间：
2011-10-18
影响因子：
11.1
通讯作者：
Driver, Jon
中科院分区：
文献类型：
--
作者：
Feredoes, Eva;Heinen, Klaartje;Driver, Jon
背外侧前额叶皮层（DLPFC）在视觉工作记忆（WM）过程中被激活，当相关信息必须在分散信息的存在下保持。然而，DLPFC可能确保WMis内容成功维持的机制尚不清楚；它可能增强神经对记忆目标的维持或抑制对干扰物的处理。为了判断这些可能性，我们在功能MRI期间应用了时间锁定经颅磁刺激（TMS），这是一种允许对受刺激的大脑区域对连接的大脑区域的影响进行因果评估的方法，并评估了这种影响在不同任务条件下如何变化。参与者完成了一项视觉WM任务，该任务要求在视觉干扰物存在或不存在的一段时间内保持视觉刺激（面部或房屋）。当干扰物存在时，它们总是来自相反的刺激类别，因此目标和干扰物在不同的后皮层区域被表征。然后，我们测量了在干扰物可能出现的延迟时间点给予DLPFC-TMS是否会调节代表记忆目标或干扰物的后脑区。我们发现DLPFC-TMS仅在有干扰物存在时才会影响后脑区，关键的是，这种影响包括代表当前记忆目标区域的活动增加。DLPFC-TMS不影响代表当前干扰物的区域。这些结果为自上而下的基于dlpfc的控制机制提供了新的因果证据，该机制促进了分心存在时WM中相关信息的成功维持。
Dorsolateral prefrontal cortex (DLPFC) is recruited during visual working memory (WM) when relevant information must be maintained in the presence of distracting information. The mechanism by which DLPFC might ensure successful maintenance of the contents of WMis, however, unclear; it might enhance neural maintenance of memory targets or suppress processing of distracters. To adjudicate between these possibilities, we applied time-locked transcranial magnetic stimulation (TMS) during functional MRI, an approach that permits causal assessment of a stimulated brain region's influence on connected brain regions, and evaluated how this influence may change under different task conditions. Participants performed a visual WM task requiring retention of visual stimuli (faces or houses) across a delay during which visual distracters could be present or absent. When distracters were present, they were always from the opposite stimulus category, so that targets and distracters were represented in distinct posterior cortical areas. We then measured whether DLPFC-TMS, administered in the delay at the time point when distracters could appear, would modulate posterior regions representing memory targets or distracters. We found that DLPFC-TMS influenced posterior areas only when distracters were present and, critically, that this influence consisted of increased activity in regions representing the current memory targets. DLPFC-TMS did not affect regions representing current distracters. These results provide a new line of causal evidence for a top-down DLPFC-based control mechanism that promotes successful maintenance of relevant information in WM in the presence of distraction.