为了检测人脑静息态下默认模式网络的功能连接状况,从静息态的脑部 fMRI 影像中提取各个脑区的血氧水平依赖(BOLD)信号,分析其质量指数函数及奇异谱函数曲线的性质,发现 BOLD信号具有一定的多重分形性。分别计算全脑160个感兴趣区域(ROI)的BOLD信号分形谱函数的3个特征参数并组成特征向量,以这些特征向量作为层次聚类,识别出包含 ROI_73(扣带回的代表节点)的簇团,该簇团与Dosenbach的研究结果比较,有25个 ROI是相同的,差异较少。
In order to detect the brain functional connectivity pattern of default mode network (DMN),The blood oxygena-tion level dependent (BOLD)signal is extracted for each ROI from the brain in resting state,it could be proved that the BOLD signal has certain multifractal properties through the analysis of quality index function and singular spectrum func-tion.By clustering feature vectors consisted of three characteristic parameters of fractal spectrum function for each ROI with hierarchical clustering method,the clusters of containing ROI_73 (representative of cingulate gyrus)can be identified.Com-pared with the research of Dosenbach,25 nodes in the cluster are the same.