Right hemispheric dominance of inhibitory control: An event-related functional MRI study

Normal human behavior and cognition are reliant on a person’s ability to inhibit inappropriate thoughts, impulses, and actions. The temporal and spatial advantages of event-related functional MRI (fMRI) were exploited to identify cortical regions that showed a transient change in fMRI signal after the withholding of a prepotent motor response. The temporal specificity of the event-related fMRI design also minimized possible contamination from response inhibition errors (i. e., commission errors) and other extraneous processes. Regions identified were strongly lateralized to the right hemisphere and included the middle and inferior frontal gyri, frontal limbic area, anterior insula, and inferior parietal lobe. Contrary to the prominence traditionally given to ventral frontal regions for response inhibition, the results suggest that response inhibition is accomplished by a distributed cortical network.

正常人类的行为与认知，依赖个体抑制不当想法、冲动与行为的能力。本研究利用事件相关功能磁共振成像（event-related functional MRI, fMRI）的时空优势，识别出个体在抑制优势运动反应后，其fMRI信号出现瞬时变化的大脑皮层区域。该事件相关fMRI设计的时间特异性，还最大程度降低了反应抑制错误（即commission errors）与其他无关认知过程带来的干扰。经识别的皮层区域呈现显著的右侧半球偏侧化，涵盖额中回、额下回、额叶边缘区、前脑岛以及顶下小叶。与传统上认为腹侧额叶区域在反应抑制中占主导地位的观点相悖，本研究结果表明，反应抑制由一个分布式的皮层网络所实现。