Keil Andreas, Stolarova Margarita, Heim Sabine, Gruber Thomas, Müller Matthias M
Department of Psychology, University of Konstanz, Germany.
Brain Topogr. 2003 Winter;16(2):101-10. doi: 10.1023/b:brat.0000006334.15919.2c.
Temporal stability of a given measurement within individual participants is a desirable property of psychophysiological measures. The present study aims to examine the reliability of high-frequency oscillatory activity in the human electroencephalogram (EEG) across 4 sessions. Convolution of the EEG time series with Morlet wavelets yielded time-frequency representations of the signal for each session. Stability of both topography and time course of gamma-band activity (GBA) was determined for two participants performing a feature-based selective attention task in four separate sessions, spaced at weekly intervals. We found high temporal stability of non-phase-locked GBA typically occurring in time ranges between 200 and 500 ms following presentation of a stimulus, both in terms of topography and time course. Early phase-locked GBA (80-120 ms) showed higher variability with respect to topography, but was consistent in terms of time course. We conclude that measures of high-frequency oscillatory activity as used in the cognitive neurosciences meet stability requirements necessary for meaningful interpretation of this parameter of brain function.
在个体参与者中，给定测量值的时间稳定性是心理生理测量的一个理想特性。本研究旨在考察人类脑电图（EEG）中高频振荡活动在4次测量期间的可靠性。EEG时间序列与Morlet小波的卷积产生了每次测量的信号时频表示。在间隔为一周的四个独立测量期间，对两名执行基于特征的选择性注意任务的参与者，确定了γ波段活动（GBA）的地形图和时间进程的稳定性。我们发现，非锁相GBA在刺激呈现后200至500毫秒的时间范围内通常具有较高的时间稳定性，无论是在地形图还是时间进程方面。早期锁相GBA（80 - 120毫秒）在地形图方面表现出较高的变异性，但在时间进程方面是一致的。我们得出结论，认知神经科学中使用的高频振荡活动测量满足对脑功能这一参数进行有意义解释所必需的稳定性要求。
