字母与矩阵工作记忆功能磁共振成像研究

目的:利用功能磁共振成像(fMRI)技术,研究健康成人工作记忆的脑激活功能区。材料和方法:12例健康成人进行字母与矩阵工作记忆两个任务的n-back试验,任务为组块设计,2-back为记忆任务,0-back为内对照;GE3.0TMRI扫描采集图像;以AFNI软件对数据分析和功能定位。结果:①字母与矩阵工作记忆2-back任务的执行正确率均低于0-back任务(P<0.01),所有受试者执行任务正确率均超过75%。②字母工作记忆激活脑区为左侧Broca区(BA44/45)、右侧与左侧前额叶腹侧(BA9/46)、右侧与左侧顶叶后部(BA7/40)、右侧与左侧前运动区(BA6)及辅助运动区(SMA,BA6/8),上述脑区激活强度(2-back相对于0-back任务激活信号改变百分比)均数分别为1.62%、3.27%、3.49%、2.42%、3.53%、2.95%、3.51%与1.79%,其中左半球激活更显著(P<0.05)。③矩阵工作记忆激活脑区为右侧与左侧BA9/46、右侧与左侧BA7/40、右侧与左侧BA6及BA6/8,激活强度分别为:4.96%、4.36%、2.60%、2.50%、2.94%、3.45%与1.83%,其中左侧BA6激活大于右侧BA6,右侧BA9/46与BA7/40激活分别大于左侧BA9/46与BA7/40(P<0.05)。结论:工作记忆存在双分离的脑功能基础,字母工作记忆为"语音环路"前额区BA9/46、左侧Broca区与BA6,左侧激活较右侧强;矩阵工作记忆为"空间模板"前额区BA9/46、BA7/40与BA6,BA9/46、BA7/40右侧激活较左侧强。

Verbal and Spatial Working Memory:A fMRI Study

Purpose:To explore brain functional areas relating to verbal and spatial working memory in healthy adults.Materials and Methods:Twelve healthy participants were tested with a verbal version and a spatial version of the n-back task during fMRI(GE 3.0T)scanning.The working memory load was manipulated across the experiments(0,2-back).fMRI data were analyzed using AFNI software according to the percentage of signal-change.Results:We found significantly lower accuracy in performance for both the verbal version and the spatial version of the 2-back task in health participants.Healthy participants showed increased activation in middorsolateral prefrontal region and Broca's area in verbal version,especially in the left brain.And the participants also showed increased activation in middorsolateral prefrontal region and superior parietal cortex in spatial version,especially in the right brain.Conclusion:These results indicate the existence of specific regions mediating the two kinds of working memory.Language loop is relating to verbal working memory,and visuospatial sketchpad is relating to spatial working memory.