Nelson James K, Reuter-Lorenz Patricia A, Sylvester Ching-Yune C, Jonides John, Smith Edward E
Department of Psychology, University of Michigan, 525 East University, Ann Arbor, MI 48109-1109, USA.
Proc Natl Acad Sci U S A. 2003 Sep 16;100(19):11171-5. doi: 10.1073/pnas.1334125100. Epub 2003 Sep 4.
Cognitive control requires the resolution of interference among competing and potentially conflicting representations. Such conflict can emerge at different points between stimulus input and response generation, with the net effect being that of compromising performance. The goal of this article was to dissociate the neural mechanisms underlying different sources of conflict to elucidate the architecture of the neural systems that implement cognitive control. By using functional magnetic resonance imaging and a verbal working memory task (item recognition), we examined brain activity related to two kinds of conflict with comparable behavioral consequences. In a trial of our item-recognition task, participants saw four letters, followed by a retention interval, and a probe letter that did or did not match one of the letters held in working memory (positive probe and negative probe, respectively). On some trials, conflict arose solely because of the current negative probe having a high familiarity, due to its membership in the immediately preceding trial's target set. On other trials, additional conflict arose because of the current negative probe having also been a positive probe on the immediately preceding trial, producing response-level conflict. Consistent with previous work, conflict due to high familiarity was associated with left prefrontal activation, but not with anterior cingulate activation. The response-conflict condition, when compared with high-familiarity conflict trials, was associated with anterior cingulate cortex activation, but with no additional left prefrontal activation. This double dissociation points to differing contributions of specific cortical areas to cognitive control, which are based on the source of conflict.
认知控制需要解决相互竞争且可能相互冲突的表征之间的干扰。这种冲突可能在刺激输入和反应产生之间的不同点出现，其净效应是损害表现。本文的目的是区分不同冲突源背后的神经机制，以阐明实施认知控制的神经系统结构。通过使用功能磁共振成像和言语工作记忆任务（项目识别），我们研究了与两种具有可比行为后果的冲突相关的大脑活动。在我们的项目识别任务试验中，参与者先看到四个字母，接着是一个保持间隔，然后是一个探测字母，该探测字母与工作记忆中保存的一个字母匹配或不匹配（分别为肯定探测和否定探测）。在某些试验中，冲突仅因当前否定探测具有高熟悉度而产生，这是因为它属于前一个试验的目标集。在其他试验中，额外的冲突因当前否定探测在前一个试验中也是肯定探测而产生，从而产生反应水平冲突。与先前的研究一致，因高熟悉度导致的冲突与左前额叶激活相关，但与前扣带回激活无关。与高熟悉度冲突试验相比，反应冲突条件与前扣带回皮质激活相关，但没有额外的左前额叶激活。这种双重分离表明特定皮质区域对认知控制的不同贡献，这是基于冲突源的。
