帕金森病患者局部场电位信号多频耦合特征分析

Cross Frequency Coupling Characteristic Analysis in Subthalamic Local Field Potentials of Parkinson's Disease

丘脑底核神经活动与帕金森病症状密切相关，其局部场电位提供了丰富的神经波动成分信息。在震颤状态下，局部场电位信号中可见震颤频率及其倍频谱峰，这种多倍频现象中各成分间的相互关系很可能与震颤发生的神经机制有关。为确定各神经活动成分间的相互耦合关系，对9名帕金森病患者局部场电位进行跨频率相关分析，结果表明在震颤频率与其倍频成分之间存在明显相关，互相关系数在0．18．0．50范围内。Granger因果分析表明震颤基频对2倍频成分、震颤基频和2倍频成分对3倍频的发生有贡献作用。在双谱分析中发现震颤基频和2倍频、3倍频成分间存在二次相位耦合作用，说明高频段倍频成分的产生与低频段倍频成分间的非线性耦合有关。本研究证实了震颤相关的基底神经节活动的多个波动成分并不独立，互相间存在线性和非线性交互作用关系，进一步揭示了震颤发生的复杂神经机制。

Pathological neural activity in subthalamic nucleus （STN） is closely related to the symptoms of Parkinson＇ s disease. Local field potentials （LFPs） recordings from subthalamic nucleus show that power spectral peaks exist at tremor, double tremor and tripble tremor frequencies, respectively. The interaction between these components in the multi-frequency tremor may be related to the generation of tremor. To study the linear and nonlinear relationship between those components, we analyzed STN LFPs from 9 Parkinson＇s disease patients using time frequency, cross correlation, Granger casuality and bi-spectral analysis. Results of the time-frequency analysis and cross-frequency correlation analysis demonstrated that the power density of those components significantly decreased as the alleviation of tremor and cross-correlation （0.18±0.50） exists during tremor period. Granger causality of the time-variant amplitude showed stronger contribution from tremor to double tremor components, and contributions from both tremor and double tremor components to triple tremor component. Quadratic phase couplings among these three components were detected by the bispectral approaches. The linear and nonlinear relationships existed among the multi-compo- nents and certainly confirmed that the dependence cross those frequencies and neurological mechanism of tremor involved complicate neural processes.