采用脑电图(EEG)相干分析法构建功能网络,目的在于研究人脑负责工作记忆(WM)的主要区域——大脑后颞叶在不同模式工作记忆过程中的作用地位和区域职能.为此设计两种实验范式,要求12名受试记忆分别表征WM的两个成分,即语音回路和视空间模板的可言辞表达的字母串和非言辞表达的图形.采集19导EEG,分别计算语音回路和视空间模板的相干系数矩阵,绘制功能网络.结果显示,与静息态相比,在语音回路和视空间模板中,后颞叶(T5、T6)与其他脑区的θ(4~7 Hz)相干明显增强(P<0.05),表明后颞叶与其他脑区的θ频段同步效应参与WM;此外,在语音回路、视空间模板的功能网络中,节点T5、T6的度差异显著,但都远高于其他节点,表明左、右后颞叶分别在语音回路、视空间模板WM中扮演着专家化区域的角色.
In this paper,the coherence method of electroencephalogram (EEG) was employed to establish functional networks to study the main areas which are responsible for the working memory (WM) —— the role and function of posterior temporal lobes presented in the processes of different WM modes.Twelve subjects performed our experiments which required the retention of either verbalizable strings of letters or abstract drawings.These two paradigms were designed specifically for corresponding to the two components of working memory-phonological loop and visual-spatial sketch pad respectively.A 19-channels EEG signal was recorded,based on which the coherent coefficient matrices were calculated.In consequence,the brain functional networks were constructed and discussed in this paper.Results showed that,compared with the resting state,for both phonological loop and visual-spatial sketch pad,significantly increased θ (4 ~7 Hz) coherence values were detected between posterior temporal lobes (T5,T6) and other brain regions (P < 0.05).This result suggested between the posterior temporal lobes and other brain regions the θ synchronization phenomenon could be observed during the process of working memory.Furthermore,the degrees of nodes T5 and T6 were largely different in the functional networks of the two components.However,both the degrees of T5 and T6 were bigger than other nodes,suggesting the left and right posterior temporal lobes may serve as specialized regions for the phonological loop and visual-spatial sketch pad respectively.