Abstract：The analysis of feature information for the prefrontal cortex EEG (electroencephalograph) theta bands (4～8 Hz) signal can reveal the function status and mechanism of the prefrontal cortex in the process of “information maintain and recall” phase within the working memory. Fifteen participants’ scalp EEG signals were collected during the experiment, in which participants did the working memory task with different memory loads, including 3 letters, 5 letters and 7 letters. The theta band signal of each electrode was extracted using morlet wavelet decomposition method. In terms of energy analysis, the Welch power spectral density was used to calculate the average power and the short time Fourier transform (STFT) was used for the timefrequency analysis. In terms of correlation analysis, the correlation coefficient based on the power spectrum between different electrodes was used for the correlation analysis and the phase locking value (PLV) between the different electrodes was used for the phase synchronization analysis. It is concluded that brain has the comparative function of the feature information of the theta band signal from the prefrontal cortex, central cortex and parietal cortex within different memory loads. The results are analysed by the paired t test and the F test of single factor analysis of variance. With the increase of the memory load, the power of the theta bands in the prefrontal cortex (electrode: Fp1, Fz, ofFp2, F3, F4) has more increased dramatically than that in the central lobe (electrode: C7, C3, Cz, C4, C8) and parietal lobe (electrode: P7, P3, Pz, P4, P8). The result has the statistical significance (P < 005, of which the Fz: P < 001 ).In terms of correlation analysis, with the lower letters memory load, the correlation coefficient of the ipsilateral regions, such as prefrontal lobe the central lobe (F3C3, F4C4), frontal lobeparietal lobe (F3P3, F4P4) is similar between the left region and right region in the brain. But with the increase of the memory load, relative to the left brain,the correlation coefficient of the right brain has increased obviously.In terms of phase synchronization, with the increase of the memory load, the right brain, such as the frontal lobethe central lobe (F4C4) and the prefrontal lobe, parietal lobe (F4P4) relative to the left brain markedly improved in phase synchronization, and the PLV compared value (PLV) increased obviously. The result has statistical significance (P < 005 ). During the “information maintain and recall” phase of the working memory, the degree of activity and informationexchange in the prefrontal cortex aresignificantly more than that in the middle and the parietal cortex. It may play a multifunction role that include maintain the information and call other cortexs. With the increase of the memory load, the brain will call more right brain cortex in working memory, and the rational logic model will translate into the perceptual image memory mode which can improve work efficiency.
李松 靳静娜 王欣 刘志朋 殷涛#*. 基于脑电θ波特征信息分析的大脑前额皮质[J]. 中国生物医学工程学报, 2015, 34(2): 143-152.
Li Song Jin Jingna Wang Xin Liu Zhipeng Yin Tao#*. The Role of the Prefrontal Cortex in the Characters Working Memory Research Based on the EEG Theta Band Characteristic Analysis. journal1, 2015, 34(2): 143-152.
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