Liu Xun, Banich Marie T, Jacobson Benjamin L, Tanabe Jody L
Department of Psychology, University of Colorado, Boulder, CO 80309-0345, USA.
Neuroimage. 2004 Jul;22(3):1097-106. doi: 10.1016/j.neuroimage.2004.02.033.
The purpose of this experiment was to directly examine the neural mechanisms of attentional control involved in the Simon task as compared to a spatial Stroop task using event-related fMRI. The Simon effect typically refers to the interference people experience when there is a stimulus-response conflict. The Stroop effect refers to the interference people experience when two attributes of the same stimulus conflict with each other. Although previous imaging studies have compared the brain activation for each of these tasks performed separately, none had done so in an integrated task that incorporates both types of interference, as was done in the current experiment. Both tasks activated brain regions that serve as a source of attentional control (dorsolateral prefrontal cortex) and posterior regions that are sites of attentional control (the visual processing stream-middle occipital and inferior temporal cortices). In addition, there were also specific brain regions activated to a significantly greater degree by one task and/or only by a single task. The brain regions significantly more activated by the Simon task were those sensitive to detection of response conflict, response selection, and planning (anterior cingulate cortex, supplementary motor areas, and precuneus), and visuospatial-motor association areas. In contrast, the regions significantly more activated by the Stroop task were those involved in biasing the processing toward the task-relevant attribute (inferior parietal cortex). These findings suggest that the interference effects of these two tasks are caused by different types of conflict (stimulus-response conflict for the Simon effect and stimulus-stimulus conflict for the Stroop effect) but both invoke similar sources of top-down modulation.
本实验的目的是使用事件相关功能磁共振成像技术，直接研究与空间斯特鲁普任务相比，西蒙任务中涉及的注意力控制的神经机制。西蒙效应通常是指当存在刺激-反应冲突时人们所经历的干扰。斯特鲁普效应是指当同一刺激的两个属性相互冲突时人们所经历的干扰。尽管先前的成像研究分别比较了执行这两种任务时的大脑激活情况，但没有一项研究像当前实验那样，在一个整合了两种干扰类型的综合任务中进行比较。这两种任务都激活了作为注意力控制源的脑区（背外侧前额叶皮层）和作为注意力控制位点的后部脑区（视觉处理流——枕中回和颞下回皮层）。此外，还有一些特定的脑区，在一种任务中被激活的程度明显更高，和/或仅在单一任务中被激活。在西蒙任务中激活程度明显更高的脑区是那些对反应冲突检测、反应选择和计划敏感的脑区（前扣带回皮层、辅助运动区和楔前叶），以及视觉空间-运动关联区。相比之下，在斯特鲁普任务中激活程度明显更高的脑区是那些参与将处理偏向与任务相关属性的脑区（顶下小叶皮层）。这些发现表明，这两种任务的干扰效应是由不同类型的冲突引起的（西蒙效应为刺激-反应冲突，斯特鲁普效应为刺激-刺激冲突），但两者都调用了类似的自上而下调制源。
