Pre-stimulus alpha (8-12 Hz) and beta (16-20 Hz) oscillations have been frequently linked to the prediction of upcoming sensory input. Do these frequency bands serve as a neural marker of linguistic prediction as well? We hypothesized that if pre-stimulus alpha and beta oscillations index language predictions, their power should monotonically relate to the degree of predictability of incoming words based on past context. We expected that the more predictable the last word of a sentence, the stronger the alpha and beta power modulation. To test this, we measured neural responses with magnetoencephalography of healthy individuals during exposure to a set of linguistically matched sentences featuring three levels of sentence context constraint (high, medium and low constraint). We observed fluctuations in alpha and beta power before last word onset, and modulations in M400 amplitude after last word onset. The M400 amplitude was monotonically related to the degree of context constraint, with a high constraining context resulting in the strongest amplitude decrease. In contrast, pre-stimulus alpha and beta power decreased more strongly for intermediate constraints, followed by high and low constraints. Therefore, unlike the M400, pre-stimulus alpha and beta dynamics were not indexing the degree of word predictability from sentence context.

中文翻译：

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Alpha / Beta振荡与句子编码之间的关系可诱导上下文信息。

刺激前的阿尔法（8-12 Hz）和贝塔（16-20 Hz）振动经常与即将到来的感觉输入的预测相关。这些频段是否也可以作为语言预测的神经标记？我们假设，如果刺激前的alpha和beta振荡索引了语言的预测，则它们的功能应与过去的上下文基于传入单词的可预测性单调相关。我们期望句子的最后一个单词越可预测，则alpha和beta功率调制越强。为了测试这一点，我们在接触一组具有三个级别的句子上下文约束（高，中和低约束）的语言匹配的句子期间，通过磁脑电图对健康个体的神经反应进行了测量。我们观察到在最后一个单词出现之前，alpha和beta幂的波动，最后一个字开始后对M400幅度进行调制和调制。M400振幅与上下文约束的程度单调相关，具有较高的约束上下文，导致幅度下降最大。相比之下，刺激前的α和β功率在中等约束条件下下降幅度更大，其次是高和低约束条件。因此，与M400不同，刺激前的alpha和beta动态不会索引句子上下文中单词可预测性的程度。