正常人工作记忆任务和静息状态下前额叶皮层内侧面的功能连接分析

目的 分析在工作记忆任务和静息两种状态下与前额叶皮层内侧面(MPFC)正、负相关脑区的分布,比较两种状态下MPFC功能连接的差异.资料与方法 采用GE 1.5 T MR扫描仪对25名正常自愿者行静息态及2-back工作记忆任务的功能磁共振成像(fMRI)实验,2-back实验采用组块设计,0-back作为对照,6个对照组块与5个任务组块交替进行.静息态全脑采集128个时相.采用SPM、AFNI对数据进行预处理.选择MPFC作为种子点与全脑其他像素进行Pearson相关分析,建立相关图.组内分析时采用随机效应模型单样本t检验,检测与MPFC明显正相关或负相关的脑区.组间分析采用配对样本t检验.检测MPFC功能连接图在2-back任务和静息状态下的差异.结果 两种状态下与MPFC正相关的脑区基本一致,属于"任务负激活网络".2-back任务状态下与MPFC负相关的脑区与"任务正激活网络"一致.静息状态下与MPFC负相关的脑区主要分布在双侧岛叶、双侧顶下小叶,且这些区域的负相关性明显高于任务状态.任务状态下负相关性高于静息状态的主要脑区包括双侧运动前区外侧(LPMA)、双侧顶叶后部(PPC)、左侧丘脑及右侧小脑半球.结论 静息及2-back任务状态下MPFC的功能连接情况不同,对于正常人在静息及任务状态下的功能连接对比研究为临床精神疾病患者的研究奠定了基础.

Functional Connectivity of Medial Part of Prefrontal Cortex in Normal Subject: a Comparing Study Between Working Memory Task and Resting State

Objective To analyze the distributions of positive-related brain areas and negative-related brain areas to medial part of the prefrontal cortex(MPFC) at working memory task and resting state respectively,and to compare the functional connectivity in MPFC at two states.Materials and Methods Twenty five normal subjects underwent block-designed functional MRI examination with GE 1.5 T MR scanne at 2-back task and resting state.Six control blocks(0-back) and five 2-back blocks ran alternately.During resting state,128 scans of whole brain were performed.The fMRI data were preprocessed by SPM and AFNI.MPFC was selected as "seed" pixel.The correlation of "seed" pixel and other pixels in whole brain was analyzed and the correlation maps were obtained using Pearson correlation.Single sample t-test based on random effect model was used to analyze positive-related brain areas and the negative-related brain areas to MPFC.Paired t-test was used to analyze the difference of functional connectivity between 2-back task and resting state.Results At 2-back task and resting state,the positive-related brain areas were same and were coincidence with those of "task-negative network".The negative-related brain areas at 2-back task were consistent with "task-positive network".At resting state,negative-related brain areas were bilateral insular lobes,inferior parietal lobes,which showed more negative correlation than that at 2-back task.At 2-back task,the brain areas which showed more negative correlation with MPFC than that at resting state,included bilateral lateral premotor area(LPMA),bilateral posterior parietal lobe(PPC),left thalamus,and right cerebellum.Conclusion The functional connectivity of MPFC was different between resting state and working memory task.This study on functional connectivity in normal subjects at resting state and task state played an important role for the studies on clinical mental diseases.