Aperiodic phase re-setting in scalp EEG of beta-gamma oscillations by state transitions at alpha-theta rates
Aperiodic phase re-setting in scalp EEG of beta-gamma oscillations by state transitions at alpha-theta rates
复制标题
DOI：
10.1002/hbm.10120
复制
发表时间：
2003-08-01
影响因子：
4.8
通讯作者：
Holmes, MD
中科院分区：
文献类型：
--
作者：
Freeman, WJ;Burke, BC;Holmes, MD
我们评估了正常受试者区域头皮EEG同步的快速变化，其空间和时间分辨率超过现有技术的10倍，具有高空间密度阵列和希尔伯特变换。使用64个电极的曲线阵列以200次/秒的速度记录EEG，电极间隔3 mm，延伸18.9 cm穿过头皮。在0.5-120 Hz的模拟通带中，在每个时间步长处计算64个迹线的分析振幅（AA）和相位（AP）。AP差近似于AP导数（瞬时频率）。来自未过滤EEG的AP显示没有可再现的模式。根据优化AP差异与在α范围中滤波的活动带通的相关性的技术，在β和γ范围中滤波是必要的。时间AP差异的大小通常在与通带中心频率对应的平均步长的+/-0.5弧度内。较大的AP差异通常在6至19 cm的距离上同步。通过最大化未滤波EEG和带通AP差异之间的相关性的共谱中的a峰，发现了检测和测量β和γ范围中AP中的这些反复跳跃的最佳通带。同步AP跳跃复发集群（CAP）在阿尔法和θ率在休息科目和肌电图。皮质通过状态的连续变化来发挥作用。从高密度阵列的EEG的希尔伯特变换可以可视化这些状态的转换与高的时间和空间分辨率，并应在相关的EEG认知有用。(C)2003 Wiley-Liss，Inc.
We evaluated the rapid changes in regional scalp EEG synchronization in normal subjects with spatial and temporal resolution exceeding prior art 10-fold with a high spatial density array and the Hilbert transform. A curvilinear array of 64 electrodes 3 mm apart extending 18.9 cm across the scalp was used to record EEG at 200/sec. Analytic amplitude (AA) and phase (AP) were calculated at each time step for the 64 traces in the analog pass band of 0.5-120 Hz. AP differences approximated the AP derivative (instantaneous frequency). The AP from unfiltered EEG revealed no reproducible patterns. Filtering was necessary in the beta and gamma ranges according to a technique that optimized the correlation of the AP differences with the activity band pass filtered in the alpha range. The sizes of temporal AP differences were usually within +/-0.5 radian from the average step corresponding to the center frequency of the pass band. Large AP differences were often synchronized over distances of 6 to 19 cm. An optimal pass band to detect and measure these recurring jumps in AP in the beta and gamma ranges was found by maximizing the a peak in the cospectrum of the correlation between unfiltered EEG and the band pass AP differences. Synchronized AP jumps recurred in clusters (CAP) at alpha and theta rates in resting subjects and with EMG. Cortex functions by serial changes in state. The Hilbert transform of EEG from high-density arrays can visualize these state transitions with high temporal and spatial resolution and should be useful in relating EEG to cognition. (C) 2003 Wiley-Liss, Inc.