Language and Computation in Neural Systems group, Max Planck Institute for Psycholinguistics, Nijmegen, Netherlands.
Language and Computation in Neural Systems group, Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands.
Elife. 2022 Jul 14;11:e77468. doi: 10.7554/eLife.77468.
Linguistic phrases are tracked in sentences even though there is no one-to-one acoustic phrase marker in the physical signal. This phenomenon suggests an automatic tracking of abstract linguistic structure that is endogenously generated by the brain. However, all studies investigating linguistic tracking compare conditions where either relevant information at linguistic timescales is available, or where this information is absent altogether (e.g., sentences versus word lists during passive listening). It is therefore unclear whether tracking at phrasal timescales is related to the content of language, or rather, results as a consequence of attending to the timescales that happen to match behaviourally relevant information. To investigate this question, we presented participants with sentences and word lists while recording their brain activity with magnetoencephalography (MEG). Participants performed passive, syllable, word, and word-combination tasks corresponding to attending to four different rates: one they would naturally attend to, syllable-rates, word-rates, and phrasal-rates, respectively. We replicated overall findings of stronger phrasal-rate tracking measured with mutual information for sentences compared to word lists across the classical language network. However, in the inferior frontal gyrus (IFG) we found a task effect suggesting stronger phrasal-rate tracking during the word-combination task independent of the presence of linguistic structure, as well as stronger delta-band connectivity during this task. These results suggest that extracting linguistic information at phrasal rates occurs automatically with or without the presence of an additional task, but also that IFG might be important for temporal integration across various perceptual domains.
语言短语即使在物理信号中没有一一对应的声学短语标记，也会在句子中被追踪到。这种现象表明大脑会自动追踪由其内在产生的抽象语言结构。然而，所有研究语言追踪的实验都将可获得语言时间尺度上的相关信息，或完全没有相关信息的情况进行了对比（例如被动聆听时的句子与单词列表）。因此，尚不清楚在短语时间尺度上的追踪是否与语言内容有关，或者这只是因为注意到了与行为相关信息相匹配的时间尺度而产生的结果。为了研究这个问题，我们在参与者接受句子和单词列表的同时，用脑磁图（MEG）记录他们的大脑活动。参与者分别执行被动、音节、单词和单词组合任务，这些任务对应于四种不同的注意速率：自然会注意到的速率、音节速率、单词速率和短语速率。我们复制了使用互信息测量的句子比单词列表在经典语言网络中具有更强的短语速率追踪的总体发现。然而，在额下回（IFG）中，我们发现了一个任务效应，表明在单词组合任务中，即使没有语言结构存在，也会进行更强的短语速率追踪，而且在这个任务中，delta 波段的连通性也更强。这些结果表明，在有或没有额外任务的情况下，以短语速率提取语言信息是自动进行的，但 IFG 可能对跨各种感知域的时间整合很重要。
