The Phase of Ongoing EEG Oscillations Predicts Visual Perception
The Phase of Ongoing EEG Oscillations Predicts Visual Perception
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DOI：
10.1523/jneurosci.0113-09.2009
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发表时间：
2009-06-17
影响因子：
5.3
通讯作者：
VanRullen, Rufin
中科院分区：
文献类型：
--
作者：
Busch, Niko A.;Dubois, Julien;VanRullen, Rufin
在大脑活动的电子记录中，振荡无处不在。虽然正在进行的振荡活动的幅度已知与感知的各个方面相关，但振荡相位对感知的影响仍然未知。特别是，由于相位变化的时间尺度比更缓慢的幅度波动快得多，相位效应可以揭示感知背后的细粒度神经机制。我们在记录EEG的同时，在个体亮度阈值处呈现短暂的闪光。虽然每次试验的刺激是相同的，但受试者检测到大约一半的闪光（命中），完全错过了另一半（错过）。在命中和未命中之间比较了试验中的相位分布。我们发现，在刺激开始前不久，两个分布中的每一个都表现出显着的相位浓度，但在不同的相位角。这种效应在theta和alpha频带中最强。在这个时间-频率范围内，振荡相位占检测性能的变异性的至少16%，并且允许在单次试验水平上预测性能。这一发现表明，视觉检测阈值随着时间的推移波动沿着与正在进行的EEG活动的阶段。这些结果支持了这样一种观点，即持续的振荡塑造了我们的感知，可能是通过为依赖于精确尖峰定时的神经代码提供时间参考框架。
Oscillations are ubiquitous in electrical recordings of brain activity. While the amplitude of ongoing oscillatory activity is known to correlate with various aspects of perception, the influence of oscillatory phase on perception remains unknown. In particular, since phase varies on a much faster timescale than the more sluggish amplitude fluctuations, phase effects could reveal the fine-grained neural mechanisms underlying perception. We presented brief flashes of light at the individual luminance threshold while EEG was recorded. Although the stimulus on each trial was identical, subjects detected approximately half of the flashes (hits) and entirely missed the other half (misses). Phase distributions across trials were compared between hits and misses. We found that shortly before stimulus onset, each of the two distributions exhibited significant phase concentration, but at different phase angles. This effect was strongest in the theta and alpha frequency bands. In this time-frequency range, oscillatory phase accounted for at least 16% of variability in detection performance and allowed the prediction of performance on the single-trial level. This finding indicates that the visual detection threshold fluctuates over time along with the phase of ongoing EEG activity. The results support the notion that ongoing oscillations shape our perception, possibly by providing a temporal reference frame for neural codes that rely on precise spike timing.