Hanslmayr Simon, Klimesch Wolfgang, Sauseng Paul, Gruber Walter, Doppelmayr Michael, Freunberger Roman, Pecherstorfer Thomas, Birbaumer Niels
Department of Physiological Psychology, University of Salzburg, Salzburg, Austria.
Cereb Cortex. 2007 Jan;17(1):1-8. doi: 10.1093/cercor/bhj129. Epub 2006 Feb 1.
An unresolved question in electroencephalogram (EEG) research is whether event-related potentials (ERPs) are generated by phase-reset or evoked response. We analyzed data of a visual feature detection task and will show 1) phase concentration in the alpha frequency range, 2) ongoing alpha activity prior to stimulus onset, 3) evoked alpha oscillation in the ERP, 4) lack of power increase during phase concentration, 5) decrease in amplitude variance during early evoked components preceding a decrease in power, and 6) the same cortical sources for induced prestimulus power and evoked poststimulus power. Because none of these data provide unequivocal evidence for phase reset, we additionally tested the basic assumption of the evoked model, which is the additivity of the evoked response on the basis of a simulation approach. Our findings suggest that nonadditive processes-typical for a phase reset-are involved in the generation of the ERP. Thus, together with the other findings this study provides unequivocal evidence for phase resetting in the human EEG.
脑电图（EEG）研究中一个尚未解决的问题是，事件相关电位（ERP）是由相位重置还是诱发反应产生的。我们分析了一项视觉特征检测任务的数据，并将展示：1）α频率范围内的相位集中；2）刺激开始前的持续α活动；3）ERP中的诱发α振荡；4）相位集中期间功率无增加；5）在功率下降之前，早期诱发成分期间幅度方差减小；6）诱发刺激前功率和诱发刺激后功率的皮质源相同。由于这些数据均未提供明确的相位重置证据，我们还基于模拟方法测试了诱发模型的基本假设，即诱发反应的可加性。我们的研究结果表明，ERP的产生涉及到相位重置典型的非加性过程。因此，本研究与其他研究结果一起为人类脑电图中的相位重置提供了明确的证据。
