Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK.
Institut für Biomagnetismus und Biosignalanalyse, Westfälische Wilhelms-Universität, Münster, Germany.
Eur J Neurosci. 2018 Oct;48(7):2551-2565. doi: 10.1111/ejn.13935. Epub 2018 Aug 3.
Recent studies have probed the role of the parieto-occipital alpha rhythm (8-12 Hz) in human visual perception through attempts to drive its neural generators. To that end, paradigms have used high-intensity strictly-periodic visual stimulation that created strong predictions about future stimulus occurrences and repeatedly demonstrated perceptual consequences in line with an entrainment of parieto-occipital alpha. Our study, in turn, examined the case of alpha entrainment by non-predictive low-intensity quasi-periodic visual stimulation within theta- (4-7 Hz), alpha- (8-13 Hz), and beta (14-20 Hz) frequency bands, i.e., a class of stimuli that resemble the temporal characteristics of naturally occurring visual input more closely. We have previously reported substantial neural phase-locking in EEG recording during all three stimulation conditions. Here, we studied to what extent this phase-locking reflected an entrainment of intrinsic alpha rhythms in the same dataset. Specifically, we tested whether quasi-periodic visual stimulation affected several properties of parieto-occipital alpha generators. Speaking against an entrainment of intrinsic alpha rhythms by non-predictive low-intensity quasi-periodic visual stimulation, we found none of these properties to show differences between stimulation frequency bands. In particular, alpha band generators did not show increased sensitivity to alpha band stimulation and Bayesian inference corroborated evidence against an influence of stimulation frequency. Our results set boundary conditions for when and how to expect effects of entrainment of alpha generators and suggest that the parieto-occipital alpha rhythm may be more inert to external influences than previously thought.
最近的研究通过尝试驱动其神经发生器来探究顶枕部 alpha 节律（8-12 Hz）在人类视觉感知中的作用。为此，各种范式使用高强度严格周期性的视觉刺激，这些刺激对未来刺激的发生产生了强烈的预测，并多次证明与顶枕部 alpha 同步的知觉后果一致。我们的研究转而考察了在 theta（4-7 Hz）、alpha（8-13 Hz）和 beta（14-20 Hz）频段内由非预测性低强度准周期性视觉刺激引起的 alpha 同步的情况，即一类更接近自然发生的视觉输入的时间特征的刺激。我们之前在所有三种刺激条件下的 EEG 记录中都报告了大量的神经相位锁定。在这里，我们研究了这种相位锁定在同一数据集中在多大程度上反映了内在 alpha 节律的同步。具体来说，我们测试了准周期性视觉刺激是否会影响顶枕部 alpha 发生器的几个特性。针对非预测性低强度准周期性视觉刺激不会引起内在 alpha 节律同步的说法，我们发现这些特性在刺激频带之间没有差异。特别是，alpha 频带发生器对 alpha 频带刺激没有表现出更高的敏感性，贝叶斯推理也证实了刺激频率没有影响的证据。我们的结果为何时以及如何期望 alpha 发生器同步的影响设定了边界条件，并表明顶枕部 alpha 节律可能比以前想象的对外部影响更为惰性。
