Dolcos Florin, Miller Brian, Kragel Philip, Jha Amishi, McCarthy Gregory
Duke UNC Brain Imaging and Analysis Center, Duke University, Durham, NC 27710, USA.
Brain Res. 2007 Jun 4;1152:171-81. doi: 10.1016/j.brainres.2007.03.059. Epub 2007 Mar 28.
Working memory (WM) comprises operations whose coordinated action contributes to our ability to maintain focus on goal-relevant information in the presence of distraction. The present study investigated the nature of distraction upon the neural correlates of WM maintenance operations by presenting task-irrelevant distracters during the interval between the memoranda and probes of a delayed-response WM task. The study used a region of interest (ROIs) approach to investigate the role of anterior (e.g., lateral and medial prefrontal cortex--PFC) and posterior (e.g., parietal and fusiform cortices) brain regions that have been previously associated with WM operations. Behavioral results showed that distracters that were confusable with the memorandum impaired WM performance, compared to either the presence of non-confusable distracters or to the absence of distracters. These different levels of distraction led to differences in the regional patterns of delay interval activity measured with event-related functional magnetic resonance imaging (fMRI). In the anterior ROIs, dorsolateral PFC activation was associated with WM encoding and maintenance, and in maintaining a preparatory state, and ventrolateral PFC activation was associated with the inhibition of distraction. In the posterior ROIs, activation of the posterior parietal and fusiform cortices was associated with WM and perceptual processing, respectively. These findings provide novel evidence concerning the neural systems mediating the cognitive and behavioral responses during distraction, and places frontal cortex at the top of the hierarchy of the neural systems responsible for cognitive control.
工作记忆（WM）由一系列操作组成，这些操作的协同作用有助于我们在存在干扰的情况下，将注意力集中在与目标相关的信息上。本研究通过在延迟反应WM任务的记忆项和探测项之间的间隔期间呈现与任务无关的干扰物，来探究干扰对WM维持操作的神经相关性的影响。该研究采用感兴趣区域（ROIs）方法，来研究先前与WM操作相关的前脑区域（如外侧和内侧前额叶皮层——PFC）和后脑区域（如顶叶和梭状皮层）的作用。行为结果表明，与存在不可混淆的干扰物或不存在干扰物相比，与记忆项可混淆的干扰物会损害WM表现。这些不同程度的干扰导致了用事件相关功能磁共振成像（fMRI）测量的延迟间隔活动的区域模式差异。在前脑ROIs中，背外侧PFC激活与WM编码、维持以及维持准备状态有关，腹外侧PFC激活与干扰抑制有关。在后脑ROIs中，顶叶后部和梭状皮层的激活分别与WM和知觉加工有关。这些发现为介导干扰期间认知和行为反应的神经系统提供了新的证据，并将额叶皮层置于负责认知控制的神经系统层次结构的顶端。
