EEG Research on Thinking Process

这个项目的目的是通过脑电分析来阐明思维的内在过程。首先，我们利用多通道遥测仪和相关技术开发了一个脑电遥测系统，以稳定地记录来自自由执行任务的受试者的脑电。在此基础上，提出了时间分辨率为1秒、频率分辨率为0.05赫兹的MEM功率谱时间序列分析方法，为正常儿童、残疾儿童和正常成人设计了三种类型的思维任务，即心算、对汉字笔画的心算和对一系列数字的心理排列。用MEM功率谱的α频段峰值频率(Pf)和总和α频段功率(PW)来指示思维任务执行过程中脑电的连续变化。对6名10~13岁的儿童进行双侧顶区脑电检查，结果如下。(1)在心理任务执行过程中，Pf和PW的时间序列呈现出几乎不变的任务相关变化(TRC‘s)。(2)右半球(P4)TRC较左半球(P3)差。(3)Pf-TRC的时程与PW略有不同。(4)心算任务的TRC时程稍晚于汉字笔画任务，大多数成年人也观察到Pf和PW的TRC。TRC的特点与儿童基本相同，此外，研究发现，TRC反映的是任务的性质，而不是任务刺激的物理性质。结果表明，MEM谱的TRC‘s是一种有用的思维过程查询指标。

The aim of this project is to clarify the inner process of thinking by use of EEG analysis. First, we developed an EEG telemetry system with multi-channel telemeter and related technologies for stable EEG recordings from unrestrained, task executing subjects. Then we also developed MEM (maximam entropy method) power spectrum time series analysis method, with time resolution of 1 second and with frequency resolution of 0.05Hz, which were much higher than those of conventional FFT power spectrum analysis.Thinking tasks of three types were designed for normal and handicapped children and for normal adults, which were mental arithmetic, mental counting of a given kanji-letter stroke, and mental arranging of a series of digits. Peak frequency in alpha band (PF) and summed alpha band power (PW) of MEM power spectrum were used to indicate serial EEG changes during the thinking task execution.EEG changes recorded at bilateral parietal areas were inquired in six children (10-13 years of age), and following results were obtained. (1) The time series of PF and PW showed nearly constant task-related changes (TRC's) during the execution of mental tasks. (2) TRC's in right hemishere (P4) were less distinct than those in left hemishere (P3). (3) The time courses of PF-TRC were a little different from the ones of PW.(4) The time courses of TRC's in mental arithmetic tasks were a little later than the ones in kanji-stroke tasks.TRC's of PF and PW were also observed in the majority of aduld subjects. The properties of TRC's were almost the same as in children, and in addition, it was found that TRC's reflected the property of tasks rather than the physical nature of task stimuli. From those results, it was concluded that TRC's of MEM spectrum was useful indicator for inquiery of thinking process.