Rotman Research Institute, Toronto, Ontario, Canada.
J Cogn Neurosci. 2011 Apr;23(4):867-79. doi: 10.1162/jocn.2010.21492. Epub 2010 Mar 29.
The ability to step outside a routine--to select a new response over a habitual one--is a cardinal function of the frontal lobes. A large body of neuroimaging work now exists pointing to increased activation within the anterior cingulate when stimuli evoke competing responses (incongruent trials) relative to when responses converge (congruent trials). However, lesion evidence that the ACC is necessary in this situation is inconsistent. We hypothesized that this may be a consequence of different task procedures (context) used in lesion and neuroimaging studies. The present study attempted to reconcile the lesion and the fMRI findings by having subjects perform clinical and experimental versions of the Stroop task during BOLD fMRI acquisition. We examined the relationship of brain activation patterns, specifically within the anterior cingulate and left dorsolateral frontal regions, to congruent and incongruent trial types in different task presentations or contexts. The results confirmed our hypothesis that ACC activity is relatively specific to unblocked-uncued incongruent Stroop conditions that have not been used in large neuropsychological studies. Moreover, the size of the behavioral Stroop interference effect was significantly correlated with activity in ACC and left dorsolateral regions, although in different directions. The current results are discussed in terms of previous proposals for the functional roles of these regions in activating, monitoring, and task setting, and the relation of these findings to the disparate reports in recent case series is considered.
摆脱常规——选择习惯性反应之外的新反应——的能力是额叶的主要功能。大量的神经影像学研究表明，当刺激引发竞争反应（不一致的试验）时，前扣带皮层的激活程度会增加，而当反应趋同时（一致的试验）则不会。然而，关于 ACC 在这种情况下是必需的的病变证据并不一致。我们假设，这可能是病变和神经影像学研究中使用的不同任务程序（上下文）的结果。本研究试图通过在 BOLD fMRI 采集期间让受试者执行临床和实验版 Stroop 任务，来调和病变和 fMRI 研究的结果。我们研究了大脑激活模式的关系，特别是在前扣带皮层和左背外侧额区的关系，以了解不同任务呈现或背景下一致和不一致的试验类型。结果证实了我们的假设，即 ACC 活动与未经提示的、未被阻断的不一致 Stroop 条件有关，而这些条件在大型神经心理学研究中并未被使用。此外，行为 Stroop 干扰效应的大小与 ACC 和左背外侧区域的活动显著相关，尽管方向不同。目前的结果是根据这些区域在激活、监测和任务设置方面的功能作用的先前建议进行讨论的，并且还考虑了这些发现与最近病例系列报告中的差异的关系。
