前额叶皮层在数字工作记忆维持中的作用:事件相关fMRI研究

目的采用事件相关功能磁共振成像(ER-fMRI)探讨前额叶皮层在工作记忆维持期的作用。方法20名正常受试者接受sternberg项目认知任务的功能磁共振成像。采用相对低负载、高负载任务。组分析方法评价维持期相对低、高负载时平均脑区激活情况;组间比较探讨高负载任务出现相关激活增加的脑区。结果维持期与双侧前额叶背外侧皮层(DLPFC)、双侧前额叶腹外侧皮层(VLPFC)、顶叶、辅助运动区(SMA)和运动前区(PMA)、视觉相关皮层激活相关,VLPFC等脑区在高负载任务中激活增加。结论工作记忆维持和操纵之间可能存在功能上的、而非神经解剖的区分。

The Role of the Prefrontal Cortex in the Maintenance of Verbal Working Memory:An Event-related fMRI Study

Objective To study the role of prefrontal cortex in maintenance of working memory(WM)using event-related functional MRI(ER-fMRI).Methods Twenty healthy subjects completed a relative lower,high load version of the sternberg item recognition task during ER-fMRI.The brain areas showing activity on average across the two loads for maintenance phase were obtained with group analysis.Load dependent activity was identified with inter-group analysis.Results The maintenance phase were relevant to the activity in dorsolateral prefrontal cortex(DLPFC),ventrolateral prefrontal cortex(VLPFC),parietal lobe,supplementary motor area(SMA)and premotor cortex(PMA).Brain regions including VLPFC showed increased activation for high load level.Conclusion Functional difference but not anatomic difference between maintenance and manipulation in brain may be exist.