额叶冲突加工机制及年老化改变的事件相关电位研究

Conflict processing of the frontal cortex and aging change:event-related potentials study

目的:探讨大脑额叶对冲突信息的加工处理机制及其年老化改变,探索敏感的事件相关电位(ERPs)指标。方法:研究对象为15例正常老年人(老年组)和15例青年成人(青年组),ERPs检查采用改良的Eriksen flanker视觉刺激范式,记录32导脑电、正确率及反应时。结果:与青年组相比,老年组反应时明显延长,反应阶段干扰效应尤其明显。老年组N380出现时间窗延迟,平均波幅两组无差异,源定位分析(LORETA)显示青年组可见双颞叶、双前额背外侧区域激活,以右侧明显;老年组主要见左颞叶、左前额背外侧、左前额内侧面区域激活。结论:在反应阶段出现冲突信息时,老年人额叶干扰控制功能减退,差异负波N380与老年人左前额背外侧、左侧颞叶等区域在反应选择、执行控制中的活动有关,且增龄改变明显。

Objective： To explore the working mechanism and age-related change of the conflict processing system of the frontal cortex. Methods： Fifteen normal elderly people and 15 youth were performed a modified Eriksen flanker paradigm, while event-related potential （ERPs）, which include 32 systerm electroencephalography, reaction time and correct rate were recorded. Results：The elderly group showed a distinct effect of reaction time and effect of conflict in the respond level compared with the youth group. The elderly group had a longer time window of N380 and same amplitude as the youth group. Low resolution brain electromagnetic tomography （LORETA） showed the bilateral temporal lobe and the dorsolateral prefrontal cortex （especially fight） were activated in the youth group, while the left temporal lobe, the left dorsolateral prefrontal cortex and left medial frontal gyrus were activated in the elderly group. Conclusion： When conflict stimuli existed in the response level, old people showed frontal interference control hypofimction. N380 reflected the activation of the left dorsolateral prefrontal cor- tex and the left temporal lobe during response selection and executive control processing in older people.