Fine spatiotemporal structure of phase in human intracranial EEG
Fine spatiotemporal structure of phase in human intracranial EEG
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DOI：
10.1016/j.clinph.2006.03.012
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发表时间：
2006-06-01
影响因子：
4.7
通讯作者：
Vanhatalo, Sampsa
中科院分区：
文献类型：
--
作者：
Freeman, Walter J.;Holmes, Mark D.;Vanhatalo, Sampsa
目的：将在动物实验中发展起来的高分辨率脑电图分析技术和理论应用于临床。方法：采用1 X 1 cm 8 X 8电极阵列，在右侧颞下回进行高空间分辨率的脑电图记录。将余弦拟合到脑电信号片段中，测量频率和相位，并计算径向对称空间模式（称为相锥）的位置、大小、潜伏期、相速度、持续时间和复发率。希尔伯特变换也被用来获得高的时间分辨率。结果：在清醒状态下，功率谱密度（PSD）的对数功率呈幂律下降，对数频率为1/f(alpha)， alpha近似于2，但峰值在标准经验范围内。在β和γ范围的相位具有空间梯度的圆锥形式。这些稳定的相锥空间模式的重置在空间上与在θ波频率下反复出现的间歇性不连续（“相滑移”）一致。锥的半功率直径为2 ~ 50+ mm；它们的持续时间具有幂律分布，其值范围从6到300+ ms，这取决于分析窗口的长度。在慢波睡眠中，PSD以1/f（α）下降，α近似于3，β - γ谱峰丢失，振荡和时空相位结构减少或不存在。结论：人和家兔清醒时脑电的时空结构具有显著的相似性。唯一明显的区别是测量尺度的不同。这些精细的脑电图时空结构在慢波睡眠中减弱或消失。意义：精细结构表明新皮层在自组织临界状态下保持稳定；清醒状态下的突触输入使新皮层远离临界状态，从而导致重新稳定的“神经雪崩”中的β - γ振荡；在慢波睡眠中减少的输入会让人回到临界状态，但会增加一些不稳定和癫痫发作的风险。(c) 2006年国际临床神经生理学联合会。爱思唯尔爱尔兰有限公司出版。版权所有。
Objective: To transfer to the clinic for humans the technology and theory for high-resolution EEG analysis that have been developed in the laboratory with animals.Methods: EEGs were recorded at high spatial resolution from a 1 X 1 cm 8 X 8 electrode array on the right inferior temporal gyrus of a patient undergoing preoperative monitoring for epilepsy surgery. Cosines were fitted to EEG segments to measure frequency and phase and compute location, size, latency, phase velocity, duration, and recurrence rate of radially symmetric spatial patterns called phase cones. The Hilbert transform was also used to get high temporal resolution.Results: In the awake state, the power spectral density (PSD) showed power-law decrease in log power with log frequency at 1/f(alpha), alpha similar to 2, but with peaks in the standard empirical ranges. The phase in beta and gamma ranges had spatial gradients in conic form. Resetting of these stable spatial patterns of phase cones was spatially coincident at intermittent discontinuities ('phase slip') recurring at theta rates. Cones had half power diameters from 2 to 50+ mm; their durations had power-law distributions with values ranging from 6 to 300+ ms depending on length of the analysis window. In slow wave sleep PSD decreased at 1/f(alpha), alpha similar to 3,with loss of beta-gamma spectral peaks and diminished or absent oscillations and spatiotemporal phase structure.Conclusions: Spatiotemporal structures in awake human and rabbit EEG showed striking similarities. The only clear differences were ascribable to differing scales of measurement. These fine spatiotemporal structures of EEG were diminished or lost in slow wave sleep.Significance: The fine structure indicates that neocortical stability is sustained at self-organized criticality; that synaptic input in the awake state drives neocortex away from criticality causing beta-gamma oscillations in re-stabilizing 'neural avalanches'; and that diminished input in slow wave sleep allows return toward criticality but with some added risk of instability and seizure. (c) 2006 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.