Department of Psychology, University of Cambridge, United Kingdom.
Brain Res. 2012 Oct 5;1477:27-36. doi: 10.1016/j.brainres.2012.08.023. Epub 2012 Aug 17.
The Stroop effect is one of the most popular models of conflict processing in neuroscience and psychology. The response conflict theory of the Stroop effect explains decreased performance in the incongruent condition of Stroop tasks by assuming that the task-relevant and the task-irrelevant stimulus features elicit conflicting response tendencies. However, to date, there is not much explicit neural evidence supporting this theory. Here we used functional near-infrared imaging (fNIRS) to examine whether conflict at the level of the motor cortex can be detected in the incongruent relative to the congruent condition of a Stroop task. Response conflict was determined by comparing the activity of the hemisphere ipsilateral to the response hand in the congruent and incongruent conditions. First, results provided explicit hemodynamic evidence supporting the response conflict theory of the Stroop effect: there was greater motor cortex activation in the hemisphere ipsilateral to the response hand in the incongruent than in the congruent condition during the initial stage of the hemodynamic response. Second, as fNIRS is still a relatively novel technology, it is methodologically significant that our data shows that fNIRS is able to detect a brief and transient increase in hemodynamic activity localized to the motor cortex, which in this study is related to subthreshold motor response activation.
斯特鲁普效应是神经科学和心理学中最受欢迎的冲突处理模型之一。斯特鲁普效应的反应冲突理论通过假设任务相关和任务无关的刺激特征引起冲突的反应倾向来解释在斯特鲁普任务的不一致条件下表现下降。然而，迄今为止，没有太多明确的神经证据支持这一理论。在这里，我们使用功能近红外光谱成像（fNIRS）来检测在斯特鲁普任务的不一致条件下是否可以检测到运动皮层水平的冲突。通过比较一致和不一致条件下对侧手的活动来确定反应冲突。首先，结果提供了明确的血液动力学证据支持斯特鲁普效应的反应冲突理论：在血液动力学反应的初始阶段，对侧手的运动皮层在不一致条件下的激活大于在一致条件下的激活。其次，由于 fNIRS 仍然是一种相对较新的技术，因此我们的数据表明 fNIRS 能够检测到局部到运动皮层的短暂和瞬态血液动力学活动增加，这在本研究中与阈下运动反应激活有关，这在方法学上具有重要意义。
