Frequency-specific brain dynamics related to prediction during language comprehension
Frequency-specific brain dynamics related to prediction during language comprehension
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DOI：
10.1016/j.neuroimage.2019.04.083
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发表时间：
2019-09-01
期刊：
影响因子：
5.7
通讯作者：
Schoffelen, Jan-Mathijs
中科院分区：
文献类型：
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作者：
Armeni, Kristijan;Willems, Roel M.;Schoffelen, Jan-Mathijs
大脑对口语的实时处理能力需要快速有效的信息处理机制。在这项研究中，我们研究了在听觉叙事理解过程中，特定频率的大脑动力学与概率语言预测模型的关系。当被试听荷兰语的故事时，我们记录下脑脑电信号的活动。使用三元统计语言模型，我们估计了故事中每个单词出现的条件概率。在单词概率的基础上，我们计算了当前单词给定上下文的不可预测性（单词困惑）和当前语言上下文的可预测性（单词熵）。然后，我们评估了不同频带的源重构MEG振荡是否作为这些语言处理指标的函数被调制。我们表明，相对于低熵状态，theta波段源动态在高状态下增加，可能反映了词汇计算。在低词熵和困惑的情况下，β波段动态增加，可能反映了正在进行的认知环境的维持。这些发现支持了这样一种观点，即大脑根据输入信号的统计特性积极地生成和评估预测的语言。
The brain's remarkable capacity to process spoken language virtually in real time requires fast and efficient information processing machinery. In this study, we investigated how frequency-specific brain dynamics relate to models of probabilistic language prediction during auditory narrative comprehension. We recorded MEG activity while participants were listening to auditory stories in Dutch. Using trigram statistical language models, we estimated for every word in a story its conditional probability of occurrence. On the basis of word probabilities, we computed how unexpected the current word is given its context (word perplexity) and how (un)predictable the current linguistic context is (word entropy). We then evaluated whether source-reconstructed MEG oscillations at different frequency bands are modulated as a function of these language processing metrics. We show that theta-band source dynamics are increased in high relative to low entropy states, likely reflecting lexical computations. Beta-band dynamics are increased in situations of low word entropy and perplexity possibly reflecting maintenance of ongoing cognitive context. These findings lend support to the idea that the brain engages in the active generation and evaluation of predicted language based on the statistical properties of the input signal.