Pritchard W S, Stam C J
Psychophysiology Laboratory, Bowman Gray Technical Center, R.J. Reynolds Tobacco Company, Winston-Salem, NC 27102, USA.
Acta Neurobiol Exp (Wars). 2000;60(1):109-21. doi: 10.55782/ane-2000-1329.
The question of nonlinearity in the human electroencephalogram (EEG) is important, since linear methods of EEG analysis are more well-developed and computationally faster than nonlinear methods. Furthermore, the presence or absence of nonlinearity has important theoretical implications for understanding the nature of the brain's oscillatory activity. Using a linear summary measure as a control, we report a failure to reject the null hypothesis of a (largely) stationary linear-Gaussian process for normal, resting, eyes-closed EEG from a single participant. We found significant evidence of nonlinearity at two occipital sites (O1 and O2) where the 8-12.5 Hz alpha rhythm was prominent. However, this element of nonlinear structure appeared trivial, as (1) we found no evidence of time irreversibility at these loci, and (2) best-fitting linear models accounted on-average for over 94% of the variance in the data with nonlinear modeling doing no better. Half of the remaining variance could be accounted for by nonstationarity. While our findings technically apply only to the one individual tested, his EEG was typical of those seen under the conditions that we employed.
人类脑电图（EEG）中的非线性问题很重要，因为EEG分析的线性方法比非线性方法发展得更完善，计算速度也更快。此外，非线性的存在与否对于理解大脑振荡活动的本质具有重要的理论意义。以一种线性汇总指标作为对照，我们报告称，对于一名参与者正常、静息、闭眼状态下的EEG，未能拒绝（很大程度上）平稳线性高斯过程的原假设。我们在两个枕叶部位（O1和O2）发现了显著的非线性证据，这两个部位8 - 12.5Hz的阿尔法节律很突出。然而，这种非线性结构因素似乎微不足道，原因如下：（1）我们在这些位点未发现时间不可逆性的证据；（2）最佳拟合线性模型平均解释了数据中超过94%的方差，非线性建模并未表现得更好。其余方差的一半可由非平稳性来解释。虽然我们的研究结果在技术上仅适用于所测试的这一个体，但他的EEG是我们所采用条件下所观察到的典型EEG。
