中国科学院心理研究所机构知识库

本研究侧重探讨认知电位模式的研究方法。本报告提出一种新的三维大脑模型建模和相应的三维插值方法－广义皮层成像技术，数值模拟表明这些方法优越于经典的最近邻插值。认知电位时空模式的一个重要问题是如何压缩巨量信息，本报告运用模糊聚类分析提取认知电位时空模式微状态并利用微状态的相似性确定最佳聚类数，获得了满意结果。神经振荡成为近年研究的热点，本报告应用多变量自回归模型实现了对多通道认知电位进行包括相干分析在内的高分辨频域分析，结合上述三维成像技术生成了反映皮层网络功能耦合的时空模式。运用Stroop范式记录到的事件相关电位来阐明这些方法和技术，9名受试参加了实验。基于F检验的统计参数映像表明Stroop效应发生在运动反应的选择、执行和监控阶段（知觉后阶段），涉及双侧皮层的广泛区域；而感觉区皮层在刺激出现后10 ms内即受到到自顶向下加工方式的调节。本报告提出了一个基于时空多标度和多元关系的认知电位时空模式描述体系。文中还对一些普遍问题进行了讨论，建议利用跨实验条件归一化控制个体差异，利用Hjorth变换削弱容积传导导致的模糊效应等。

This report mainly focused on methodology of spatiotemporal patterns (STP) of cognitive potentials or event-related potentials (ERP). The representation of STP of brain wave is an important issue in the research of neural assemblies. This paper described methods of parametric 3D head or brain modeling and its corresponding interpolation for functional imaging based on brain waves. The 3D interpolation method is an extension of cortical imaging technique. It can be used with transformed domain features of brain wave on realistic head or brain models. The simulating results suggests that it is a better method in comparison with the global nearest neighbor technique. A stable and definite STP of brainwave referred as microstate may become basic element for comprehending sophisticated cognitive processes. Fuzzy c-mean algorithm was applied to segmentation STPs of ERP into microstates and corresponding membership functions. The optimal microstate number was estimated with both the trends of objective function against increasing clustering number and the decorrelation technique base don microstate shape similarity. Comparable spatial patterns may occur at different moments in time with fuzzy indices and thus the serial processing limit generated from behavioral methods has been break through. High-resolution frequency domain analysis was carried out with multivariate autoregressive model. Bases on a 3D interpolation mentioned above, visualization of dynamical coordination of cerebral network was realized with magnitude-squared partial coherence. Those technique illustrated with multichannel ERP of 9 subjects when they undertook Strop task. Stroop effects involves several regions during post-perception stage with technique of statistical parameter mapping based F-test [SPM(F)]. As SPM(F) suggested task effects occurred within 100 ms after stimuli presentation involved several sensory regions, it may reflect the top-down processing effect.