TEMPORAL FLUCTUATIONS IN COHERENCE OF BRAIN WAVES
TEMPORAL FLUCTUATIONS IN COHERENCE OF BRAIN WAVES
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DOI：
10.1073/pnas.92.25.11568
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发表时间：
1995-12-05
影响因子：
11.1
通讯作者：
SPENCER, SS
中科院分区：
文献类型：
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作者：
BULLOCK, TH;MCCLUNE, MC;SPENCER, SS
作为一种动态结构的测量指标，对人类脑电图（EEG）中0.3到100Hz之间相干性的短期波动进行了研究，研究数据来自慢性硬膜下相距5 - 10mm的大电极在颞叶、额叶和顶叶的记录，以及在睡眠、清醒和癫痫发作状态下颞叶深部（包括海马体）的颅内探头记录。每秒或更短时间计算一次的相邻部位之间相干性的时间序列在稳定性上随时间变化很大；有时它能稳定半分钟或更久。在2分钟的样本内，在几秒到几十秒的时间尺度内，所有频段的相干性通常会波动2 - 3倍。这些波动的时间序列的功率谱很宽，延伸到0.02Hz或更低频率，且偏向较低频率；高于0.5Hz的功率很小。一些记录显示出明显的波动，其优势持续时间为5 - 15秒，要么不规则，要么准节律性地在0.1Hz左右有一个宽峰。在大多数记录中，周期性在统计学上不显著。在我们的采样中，我们没有发现大脑各叶、硬膜下电极和深部电极之间，或者睡眠和清醒状态之间存在一致的差异。癫痫发作通常会提高所有频率的平均相干性，并可能因天花板效应而减少波动。不同频段的相干性时间序列呈正相关（总体相关系数为0.45）；显著的非独立性至少延伸两个倍频程。相干性波动具有很强的局部性；相邻电极的时间序列与最近邻电极对（相距10mm）的相关系数平均约为0.4，与隔一个邻居的电极对（相距20mm）的相关系数降至约0.2，并且……
As a measure of dynamical structure, shortterm fluctuations of coherence between 0.3 and 100 Hz in the electroencephalogram (EEG) of humans were studied from recordings made by chronic subdural macroelectrodes 5-10 mm apart, on temporal, frontal, and parietal lobes, and from intracranial probes deep in the temporal lobe, including the hippocampus, during sleep, alert, and seizure states. The time series of coherence between adjacent sites calculated every second or less often varies widely in stability over time; sometimes it is stable for half a minute or more, Within 2-min samples, coherence commonly fluctuates by a factor up to 2-3, in all bands, within the time scale of seconds to tens of seconds. The power spectrum of the time series of these fluctuations is broad, extending to 0.02 Hz or slower, and is weighted toward the slower frequencies; little power is faster than 0.5 Hz. Some records show conspicuous swings with a preferred duration of 5-15 s, either irregularly or quasirhythmically with a broad peak around 0.1 Hz. Periodicity is not statistically significant in most records, In our sampling, we have not found a consistent difference between lobes of the brain, subdural and depth electrodes, or sleeping add waking states, Seizures generally raise the mean coherence in all frequencies and may reduce the fluctuations by a ceiling effect, The coherence time series of different bands is positively correlated (0.45 overall); significant nonindependence extends for at least two octaves, Coherence fluctuations are quite local; the time series of adjacent electrodes is correlated with that of the nearest neighbor pairs (10 mm) to a coefficient averaging approximate to 0.4, falling to approximate to 0.2 for neighbors-but-one (20 mm) and to