Montez Teresa, Poil Simon-Shlomo, Jones Bethany F, Manshanden Ilonka, Verbunt Jeroen P A, van Dijk Bob W, Brussaard Arjen B, van Ooyen Arjen, Stam Cornelis J, Scheltens Philip, Linkenkaer-Hansen Klaus
Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal.
Proc Natl Acad Sci U S A. 2009 Feb 3;106(5):1614-9. doi: 10.1073/pnas.0811699106. Epub 2009 Jan 21.
Encoding and retention of information in memory are associated with a sustained increase in the amplitude of neuronal oscillations for up to several seconds. We reasoned that coordination of oscillatory activity over time might be important for memory and, therefore, that the amplitude modulation of oscillations may be abnormal in Alzheimer disease (AD). To test this hypothesis, we measured magnetoencephalography (MEG) during eyes-closed rest in 19 patients diagnosed with early-stage AD and 16 age-matched control subjects and characterized the autocorrelation structure of ongoing oscillations using detrended fluctuation analysis and an analysis of the life- and waiting-time statistics of oscillation bursts. We found that Alzheimer's patients had a strongly reduced incidence of alpha-band oscillation bursts with long life- or waiting-times (< 1 s) over temporo-parietal regions and markedly weaker autocorrelations on long time scales (1-25 seconds). Interestingly, the life- and waiting-times of theta oscillations over medial prefrontal regions were greatly increased. Whereas both temporo-parietal alpha and medial prefrontal theta oscillations are associated with retrieval and retention of information, metabolic and structural deficits in early-stage AD are observed primarily in temporo-parietal areas, suggesting that the enhanced oscillations in medial prefrontal cortex reflect a compensatory mechanism. Together, our results suggest that amplitude modulation of neuronal oscillations is important for cognition and that indices of amplitude dynamics of oscillations may prove useful as neuroimaging biomarkers of early-stage AD.
记忆中信息的编码和保留与神经元振荡幅度持续增加长达数秒有关。我们推断，随着时间推移振荡活动的协调对于记忆可能很重要，因此，阿尔茨海默病（AD）中振荡的幅度调制可能异常。为了验证这一假设，我们在19名被诊断为早期AD的患者和16名年龄匹配的对照受试者闭眼休息期间测量了脑磁图（MEG），并使用去趋势波动分析以及振荡爆发的寿命和等待时间统计分析来表征持续振荡的自相关结构。我们发现，阿尔茨海默病患者颞顶叶区域长寿命或等待时间（<1秒）的α波段振荡爆发发生率大幅降低，且在长时间尺度（1 - 25秒）上自相关性明显较弱。有趣的是，内侧前额叶区域θ振荡的寿命和等待时间大大增加。虽然颞顶叶α振荡和内侧前额叶θ振荡都与信息的检索和保留有关，但早期AD的代谢和结构缺陷主要出现在颞顶叶区域，这表明内侧前额叶皮质中增强的振荡反映了一种代偿机制。总之，我们的结果表明神经元振荡的幅度调制对认知很重要，并且振荡幅度动态指标可能被证明是早期AD的有用神经影像学生物标志物。
