Cortical and subcortical correlates of electroencephalographic alpha rhythm modulation
Cortical and subcortical correlates of electroencephalographic alpha rhythm modulation
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DOI：
10.1152/jn.00721.2004
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发表时间：
2005-05-01
影响因子：
2.5
通讯作者：
Seifritz, E
中科院分区：
文献类型：
--
作者：
Feige, B;Scheffler, K;Seifritz, E
脑电图(EEG) α节律的神经相关性尚不清楚。在这里，我们将清醒人的脑电图α节律与功能性磁共振成像（fMRI）确定的血氧水平依赖性（BOLD）信号变化联系起来。在睁眼和闭眼以及听觉刺激和沉默条件下，与功能磁共振成像同时记录地形脑电图。利用独立分量分析将脑电分离成时间独立性最大的空间分量。α分量振幅和刺激条件作为fMRI信号时间过程的一般线性模型回归量。在两种范式中，当假设一个标准的BOLD反应曲线（在6秒左右达到最大效果）时，脑电图α分量幅值与枕区BOLD信号减少相关，而与丘脑无关。然而，独立于协议条件的α回归因子部分显示丘脑和中脑显著正相关，EEG和BOLD信号之间的平均时间延迟约为2.5 s。脑电图α振幅与初级和次级视觉区BOLD信号之间的负相关表明，广泛的丘脑皮质同步与脑代谢降低有关。虽然这种关联的时间关系与α节律变化同时发生的代谢变化是一致的，但发现丘脑内侧和中脑前部的位置与短时间滞后相关。假设一个典型的血流动力学反应函数，这一发现表明活动比实际的脑电图变化早几秒钟。
Neural correlates of electroencephalographic ( EEG) alpha rhythm are poorly understood. Here, we related EEG alpha rhythm in awake humans to blood-oxygen-level-dependent ( BOLD) signal change determined by functional magnetic resonance imaging ( fMRI). Topographical EEG was recorded simultaneously with fMRI during an open versus closed eyes and an auditory stimulation versus silence condition. EEG was separated into spatial components of maximal temporal independence using independent component analysis. Alpha component amplitudes and stimulus conditions served as general linear model regressors of the fMRI signal time course. In both paradigms, EEG alpha component amplitudes were associated with BOLD signal decreases in occipital areas, but not in thalamus, when a standard BOLD response curve ( maximum effect at similar to 6 s) was assumed. The part of the alpha regressor independent of the protocol condition, however, revealed significant positive thalamic and mesencephalic correlations with a mean time delay of similar to 2.5 s between EEG and BOLD signals. The inverse relationship between EEG alpha amplitude and BOLD signals in primary and secondary visual areas suggests that widespread thalamocortical synchronization is associated with decreased brain metabolism. While the temporal relationship of this association is consistent with metabolic changes occurring simultaneously with changes in the alpha rhythm, sites in the medial thalamus and in the anterior midbrain were found to correlate with short time lag. Assuming a canonical hemodynamic response function, this finding is indicative of activity preceding the actual EEG change by some seconds.