额叶外伤后早期数字工作记忆的fMRI研究

fMRI Study of Digital Working Memory after Traumatic Frontal Lobe Injury

目的:利用功能磁共振成像技术研究额叶外伤后,执行工作记忆任务时脑结构损伤与脑激活功能区的改变。材料和方法:对10例额叶外伤后早期患者(伤后平均31d,其中男性7例,女性3例;平均年龄30.1年)和12例正常志愿者作为对照组(男性7例,女性5例;平均年龄26.9年)分别进行2位和4位数字的正反序工作记忆的实验,使用single-trial设计方法;GE3.0T磁共振机扫描、采集图像,运用AFNI软件包进行数据分析。结果:①正常对照组反序4位数字任务大于正序4位数字脑区有辅助运动区SMA,双侧背外侧前额叶,左侧顶叶,右侧角回;②患者组反序4位数字任务大于正序4位数字的脑区有左侧枕叶;③正常对照组反序4位数字任务大于患者组的部位有左侧DLPFC,左侧角回;正序4位数字大于患者组的部位有左侧枕叶,右侧角回;④患者组反序4位数字任务时大于对照组的部位有楔状回,右侧Broca区;正序4位数字大于对照组的部位有右侧初级运动区MA,右侧额极区。结论:前额叶在脑工作记忆网络中处于重要节点,大脑右侧半球在工作记忆系统中起到巨大代偿作用的脑资源,fMRI提供认知功能损伤的影像学依据,应在临床上发挥更大作用。

Purpose： To examine the changes of brain activation while performing a digital working memory in persons with traumatic frontal lobe injury and healthy controls by fMRI. Matreials and Methods： FMRI was used to assess brain activation during a forword and backword digital span working memory task in 10 patients with TBI and 12 healthy controls, single - trial designed measure was adopted. Images were acquired by GE 3.0T magnet and analysed using AFNI.Results： The activation increased in both DLPFC, SMA, left parietal lobe and right angular gyms in healthy controls comparing with backword 4 and forward 4 digital span,but only left occipital lobe showed more activation in patients with backword 4 comparing forward 4 task. The healthey controls showed stronger activation in left DLPFC, left angular gyrns（backward 4 task） and left occipital lobe , right angular gyrns （forward 4 task） than patients, and the patients showed more activation in right motor area, cuneate lobe（backward 4 task） and right Broca and frontal pole （forward 4 task） than healthy controls. Conclusion： Prefrontal lobe is the key point in the working memory net, and right hemisphere can provide great compensation resource when needed in the net; FMRI can explore how the working memory functions are reorganlsed after TBI, and supply cognitive impaired evidence in neuroimage information.