Gómez Carlos M, Angulo-Ruíz Brenda Y, Muñoz Vanesa, Rodriguez-Martínez Elena I
Human Psychobiology lab, Experimental Psychology Department, Psychology school, University of Sevilla, c/Camilo José Cela s/n, 41018 Sevilla, Spain.
Evolutive and Developmental Psychology Department, Psychology school, University of Sevilla, Sevilla, Spain.
Cogn Neurodyn. 2022 Jun;16(3):591-608. doi: 10.1007/s11571-021-09742-6. Epub 2021 Nov 7.
The ubiquitous brain oscillations occur in bursts of oscillatory activity. The present report tries to define the statistical characteristics of electroencephalographical (EEG) bursts of oscillatory activity during resting state in humans to define (i) the statistical properties of amplitude and duration of oscillatory bursts, (ii) its possible correlation, (iii) its frequency content, and (iv) the presence or not of a fixed threshold to trigger an oscillatory burst. The open eyes EEG recordings of five subjects with no artifacts were selected from a sample of 40 subjects. The recordings were filtered in frequency ranges of 2 Hz wide from 1 to 99 Hz. The analytic Hilbert transform was computed to obtain the amplitude envelopes of oscillatory bursts. The criteria of thresholding and a minimum of three cycles to define an oscillatory burst were imposed. Amplitude and duration parameters were extracted and they showed durations between hundreds of milliseconds and a few seconds, and peak amplitudes showed a unimodal distribution. Both parameters were positively correlated and the oscillatory burst durations were explained by a linear model with the terms peak amplitude and peak amplitude of amplitude envelope time derivative. The frequency content of the amplitude envelope was contained in the 0-2 Hz range. The results suggest the presence of amplitude modulated continuous oscillations in the human EEG during the resting conditions in a broad frequency range, with durations in the range of few seconds and modulated positively by amplitude and negatively by the time derivative of the amplitude envelope suggesting activation-inhibition dynamics. This macroscopic oscillatory network behavior is less pronounced in the low-frequency range (1-3 Hz).
普遍存在的脑振荡以振荡活动的突发形式出现。本报告试图定义人类静息状态下脑电图（EEG）振荡活动突发的统计特征，以确定（i）振荡突发的幅度和持续时间的统计特性，（ii）其可能的相关性，（iii）其频率成分，以及（iv）触发振荡突发是否存在固定阈值。从40名受试者的样本中选择了5名无伪迹受试者的睁眼EEG记录。记录在1至99Hz的2Hz宽频率范围内进行滤波。计算解析希尔伯特变换以获得振荡突发的幅度包络。施加了阈值标准和至少三个周期来定义振荡突发。提取了幅度和持续时间参数，它们显示出数百毫秒到几秒的持续时间，峰值幅度呈现单峰分布。两个参数呈正相关，振荡突发持续时间由具有峰值幅度和幅度包络时间导数峰值幅度项的线性模型解释。幅度包络的频率成分包含在0 - 2Hz范围内。结果表明，在静息条件下，人类EEG在较宽频率范围内存在幅度调制的连续振荡，持续时间在几秒范围内，由幅度正向调制，由幅度包络的时间导数负向调制，提示激活 - 抑制动力学。这种宏观振荡网络行为在低频范围（1 - 3Hz）不太明显。
