中文摘要：

基于非线性Wigner-Ville distribution（WVD）方法,对大鼠在工作记忆过程中前额叶皮层多通道局部场电位（local field potentials,LFPs）进行相位同步分析,研究LFPs与工作记忆有关的θ及γ频段的同步振荡模式及其对工作记忆事件的编码。实验数据为大鼠在工作记忆过程中前额叶皮层的16通道LFPs,应用带通滤波提取每个通道LFPs的θ与γ频段,应用Hilbert变换分别提取其相位,选取平均放电频率最高的通道作为参考通道。取计算窗口为50 ms,移动窗口步长为12.5 ms,从初始窗口开始,计算每个窗口中各通道LFP的θ与γ频段的相位序列对参考通道相位序列的非线性WVD项,然后计算每个窗口中各通道LFP的θ与γ频段的相位序列的线性WVD项,分别获得这两个频段同步振荡的时空分布模式。结果显示,在工作记忆事件发生过程中,LFPs的θ和γ频段相位的非线性WVD项出现同步振荡,LFPs的θ频段相位的线性WVD项出现同步振荡而γ频段相位的线性WVD项未出现同步振荡。表明多通道LFPs的θ和γ频段相位的非线性WVD项能有效地编码工作记忆事件,LFPs相位的线性WVD项只能在θ频段编码工作记忆事件,在γ频段不能编码工作记忆事件。

英文摘要：

This work studied phase synchronous oscillation modes and encoding for working memory event in θ and γ bands of multi-channel LFPs based on Wigner-Ville distribution（WVD）.Experimental data were 16-channel LFPs acquired from prefrontal cortex of rats during working memory task related to the event 0~ 7 s.Band-pass filtering was applied to obtain LFPs＇ θ and γ bands and then Hilbert transform was used to extract the phase sequences of θ and γ bands.After choosing the reference channel which had the medium average firing rate,the WVD was used to calculate in each window between channel phase sequence of LFPs＇ θ and γ bands and reference channel phase sequence over a sliding 50 ms multi-taper window,with 12.5 ms overlapping.Then the nonlinear terms of LFPs＇ θ and γ bands were obtained.The WVD was also used to calculate phase sequence of LFPs＇ θ and γ bands in each window to obtain linear terms of LFPs＇ θ and γ bands.The results showed that obvious synchronous oscillation existed in the nonlinear WVD terms of LFPs＇ θ and γ bands,and synchronous oscillation existed in the linear WVD terms of LFPs＇ θ band while the γ band did not exist during the working memory.The results suggested that the nonlinear terms of LFPs＇ θ and γ bands encoded working memory event effectively,while the linear terms only encoded working memory event on θ band.