Center for Computational and Integrative Biology, Rutgers University, Camden, NJ, 08102, USA.
Physics Department, Rutgers University, Camden, NJ, 08102, USA.
Sci Rep. 2017 Nov 17;7(1):15758. doi: 10.1038/s41598-017-15966-6.
Evidence suggests that electroencephalographic (EEG) activity extends far beyond the traditional frequency range. Much of the prior study of >120 Hz EEG is in epileptic brains. In the current work, we measured EEG activity in the range of 200 to 2000 Hz, in the brains of healthy, spontaneously behaving rats. Both arrhythmic (1/f-type) and rhythmic (band) activities were identified and their properties shown to depend on EEG-defined stage of sleep/wakefulness. The inverse power law exponent of 1/f-type noise is shown to decrease from 3.08 in REM and 2.58 in NonREM to a value of 1.99 in the Waking state. Such a trend represents a transition from long- to short-term memory processes when examined in terms of the corresponding Hurst index. In addition, treating the 1/f-type activity as baseline noise reveals the presence of two, newly identified, high frequency EEG bands. The first band (ψ) is centered between 260-280 Hz; the second, and stronger, band is a broad peak in the 400-500 Hz range (termed ω). Both of these peaks display lognormal distributions. The functional significance of these frequency bands is supported by the variation in the strength of the peaks with EEG-defined sleep/wakefulness.
有证据表明，脑电图（EEG）活动远远超出了传统的频率范围。先前对>120Hz EEG 的大部分研究都集中在癫痫患者的大脑中。在当前的工作中，我们测量了健康、自发行为大鼠大脑中 200 到 2000Hz 的 EEG 活动。确定了不规则（1/f 型）和有节奏（波段）活动，并表明它们的特性取决于 EEG 定义的睡眠/觉醒阶段。1/f 型噪声的逆幂律指数从 REM 的 3.08 和非 REM 的 2.58 降低到清醒状态的 1.99。从短期和长期记忆过程的角度来看，这种趋势代表了一种从长时记忆到短期记忆过程的转变，而 Hurst 指数则可以反映这一点。此外，将 1/f 型活动视为基线噪声，可以揭示存在两个新识别的高频 EEG 波段。第一个波段（ψ）位于 260-280Hz 之间；第二个更强的波段是 400-500Hz 范围内的一个宽峰（称为ω）。这两个峰都显示出对数正态分布。这些频率带的功能意义得到了 EEG 定义的睡眠/觉醒状态与峰强度变化的支持。
