Mäki-Marttunen Veronica, Hagen Thomas, Espeseth Thomas
Department of Psychology, University of Oslo, Postbox 1094, 0317, Oslo, Norway.
Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Ullevål Hospital, Building 49, Kirkeveien 166, Postbox 4956, 0424, Oslo, Norway.
Cogn Affect Behav Neurosci. 2019 Aug;19(4):945-965. doi: 10.3758/s13415-019-00691-6.
Cognitive control is a highly dynamic process that relies on flexible engagement of prefrontal areas and of neuromodulatory systems in order to adapt to changing demands. A range of internal and external factors come into play when individuals engage in a task requiring cognitive control. Here we investigated whether increased working memory (WM) demands would induce a flexible change in cognitive control mode in young healthy individuals. We developed a novel variant of the well-known AX-continuous performance task (AX-CPT). We manipulated the cognitive demands of maintaining task-relevant contextual information and studied the impact of this manipulation on behavior and brain activity. We expected that low WM load would allow for a more effortful, proactive strategy, while high WM load would induce a strategy of less effortful, stimulus-driven reactive control. In line with our hypothesis, a web-based experiment revealed that increased load was associated with more reactive behavioral responses, and this finding was independently replicated in behavioral data acquired in the MRI scanner. The results from brain activity showed that the right dorsolateral prefrontal cortex was activated by cues in the proactive mode and by probes in the reactive mode. The analysis of task-induced brain stem activity indicated that both the dopaminergic and noradrenergic systems are involved in updating context representations, and that, respectively, these systems mediate a gating signal to the control network and are involved in the dynamic regulation of task engagement.
认知控制是一个高度动态的过程，它依赖于前额叶区域和神经调节系统的灵活参与，以适应不断变化的需求。当个体从事需要认知控制的任务时，一系列内部和外部因素都会发挥作用。在这里，我们研究了工作记忆（WM）需求的增加是否会在年轻健康个体中诱导认知控制模式的灵活变化。我们开发了一种著名的AX连续性能任务（AX-CPT）的新颖变体。我们操纵了维持与任务相关的情境信息的认知需求，并研究了这种操纵对行为和大脑活动的影响。我们预计，低WM负荷将允许采用更费力的主动策略，而高WM负荷将诱导采用不那么费力的、刺激驱动的反应性控制策略。与我们的假设一致，一项基于网络的实验表明，负荷增加与更多的反应性行为反应相关，并且这一发现独立地在MRI扫描仪中获取的行为数据中得到了重复。大脑活动的结果表明，右侧背外侧前额叶皮层在主动模式下被线索激活，在反应模式下被探测激活。对任务诱导的脑干活动的分析表明，多巴胺能和去甲肾上腺素能系统都参与了情境表征的更新，并且这些系统分别介导了一个向控制网络的门控信号，并参与了任务参与的动态调节。
