Gamma power is phase-locked to posterior alpha activity.
Gamma power is phase-locked to posterior alpha activity.
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DOI：
10.1371/journal.pone.0003990
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发表时间：
2008
期刊：
影响因子：
3.7
通讯作者：
Jensen O
中科院分区：
文献类型：
--
作者：
Osipova D;Hermes D;Jensen O
在人类和动物的大量研究中，已经报道了不同频段的神经元振荡。虽然很明显，这些振荡在认知过程中发挥着重要作用，但不同频段的振荡是如何相互作用的仍不清楚。在这项研究中，我们研究了健康受试者闭眼休息时脑磁图活动的相位功率锁定。为了检验交叉频率耦合，我们计算了给定频带内功率的时间进程与每个通道内的信号本身之间的相干性。使用滑动渐变时间窗口和傅立叶变换来计算功率的时间进程。我们的发现表明，高频伽马功率(30-70赫兹)被锁相为正在进行的脑磁图信号中的阿尔法振荡(8-13赫兹)。该耦合的地形图类似于α次方的地形图，并且在枕区最强。有趣的是，伽马活动本身在功率谱中并不明显，只有在与阿尔法相相关的研究中才能被检测到。来自癫痫受试者的颅内数据证实了这些发现，尽管阿尔法和伽马波段都有减慢。对这种现象的一种试探性解释是，视觉系统在阿尔法周期的大部分时间都受到抑制，而在特定阿尔法阶段(如谷底)伽马活动的爆发反映了兴奋的窗口。
Neuronal oscillations in various frequency bands have been reported in numerous studies in both humans and animals. While it is obvious that these oscillations play an important role in cognitive processing, it remains unclear how oscillations in various frequency bands interact. In this study we have investigated phase to power locking in MEG activity of healthy human subjects at rest with their eyes closed. To examine cross-frequency coupling, we have computed coherence between the time course of the power in a given frequency band and the signal itself within every channel. The time-course of the power was calculated using a sliding tapered time window followed by a Fourier transform. Our findings show that high-frequency gamma power (30–70 Hz) is phase-locked to alpha oscillations (8–13 Hz) in the ongoing MEG signals. The topography of the coupling was similar to the topography of the alpha power and was strongest over occipital areas. Interestingly, gamma activity per se was not evident in the power spectra and only became detectable when studied in relation to the alpha phase. Intracranial data from an epileptic subject confirmed these findings albeit there was slowing in both the alpha and gamma band. A tentative explanation for this phenomenon is that the visual system is inhibited during most of the alpha cycle whereas a burst of gamma activity at a specific alpha phase (e.g. at troughs) reflects a window of excitability.
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影响因子：
5.3
作者：
Jokisch, Daniel;Jensen, Ole
通讯作者：
Jensen, Ole
影响因子：
5.6
作者：
MIYAUCHI, T;ENDO, K;HAGIMOTO, H
通讯作者：
HAGIMOTO, H
影响因子：
3.4
作者：
Nikulin, Vadim V.;Linkenkaer-Hansen, Klaus;Curio, Gabriel
通讯作者：
Curio, Gabriel
DOI：
10.1016/s0013-4694(98)00026-1
发表时间：
1998-06-01
期刊：
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY
影响因子：
--
作者：
Díaz, GF;Virués, T;Valdés, P
通讯作者：
Valdés, P
影响因子：
5.3
作者：
Palva, JM;Palva, S;Kaila, K
通讯作者：
Kaila, K