Neural cascade of conflict processing: Not just time-on-task.
Neural cascade of conflict processing: Not just time-on-task.
复制标题
DOI：
10.1016/j.neuropsychologia.2016.12.022
复制
发表时间：
2017-02
期刊：
影响因子：
2.6
通讯作者：
Woldorff MG
中科院分区：
文献类型：
--
作者：
McKay CC;van den Berg B;Woldorff MG
在视觉冲突任务（如Stroop或flanker）中，相对于一致的任务，不一致的任务的反应时间（RTs）通常更长。与刺激冲突处理相关的两个事件相关电位（ERP）成分是前额-中央、不一致相关负性复合体（Ninc）和后验后正复合体（LPC），它们来源于不一致负一致试验的ERP差波。然而，这些影响或其他不一致的神经测量（例如，前扣带的fMRI反应）是否反映了真正的冲突处理，或者这些影响是否主要来自不同的任务时间，这一点一直受到质疑。为了解决这个问题，我们在两个行为任务中利用高时间分辨率ERP测量大脑活动。第一个任务是一个改进的埃里克森侧卫范式（具有一致性和不一致性试验），用于唤起与冲突相关的经典RT和ERP效应。在非冲突比较条件下，被试在视觉上对单个刺激进行区分（有容易和困难区分条件）。在行为上，这些参数被滴定以产生相似的冲突和困难的RT效应（27 ms）。在神经上，两种任务内对比都表现出最初的额-中枢负极性波（n2 -潜伏期效应），但随后它们分道扬镳。在难度差波中，初始负性直接进入后LPC，而在不一致性对比中，初始负性之后出现第二个额中央负性峰（Ninc），随后出现潜伏期较长的LPC。这些结果提供了明确的证据，证明对不一致刺激输入的较长处理时间不仅反映了任务时间或难度，而且包括了真正的冲突处理成分。
In visual conflict tasks (e.g., Stroop or flanker), response times (RTs) are generally longer on incongruent trials relative to congruent ones. Two event-related-potential (ERP) components classically associated with the processing of stimulus conflict are the fronto-central, incongruency-related negativity (Ninc) and the posterior late-positive complex (LPC), which are derived from the ERP difference waves for incongruent minus congruent trials. It has been questioned, however, whether these effects, or other neural measures of incongruency (e.g., fMRI responses in the anterior cingulate), reflect true conflict processing, or whether such effects derive mainly from differential time-on-task. To address this question, we leveraged high-temporal-resolution ERP measures of brain activity during two behavioral tasks. The first task, a modified Erikson flanker paradigm (with congruent and incongruent trials), was used to evoke the classic RT and ERP effects associated with conflict. In the second, a non-conflict comparison condition, participants visually discriminated a single stimulus (with easy and hard discrimination conditions). Behaviorally, the parameters were titrated to yield similar RT effects of conflict and difficulty (27 ms). Neurally, both within-task contrasts showed an initial fronto-central negative-polarity wave (N2-latency effect), but they then diverged. In the difficulty difference wave, the initial negativity led directly into the posterior LPC, whereas in the incongruency contrast the initial negativity was followed a by a second fronto-central negative peak (Ninc), which was then followed by a considerably longer-latency LPC. These results provide clear evidence that the longer processing for incongruent stimulus inputs do not just reflect time-on-task or difficulty, but include a true conflict-processing component.