Laboratoire des Systèmes Perceptifs, UMR 8248, CNRS, France; Département d'Etudes Cognitives, Ecole Normale Supérieure, PSL University, France.
Laboratoire des Systèmes Perceptifs, UMR 8248, CNRS, France; Département d'Etudes Cognitives, Ecole Normale Supérieure, PSL University, France.
Neuroimage. 2019 Aug 1;196:237-247. doi: 10.1016/j.neuroimage.2019.04.037. Epub 2019 Apr 13.
Humans comprehend speech despite the various challenges such as mispronunciation and noisy environments. Our auditory system is robust to these thanks to the integration of the sensory input with prior knowledge and expectations built on language-specific regularities. One such regularity regards the permissible phoneme sequences, which determine the likelihood that a word belongs to a given language (phonotactic probability; "blick" is more likely to be an English word than "bnick"). Previous research demonstrated that violations of these rules modulate brain-evoked responses. However, several fundamental questions remain unresolved, especially regarding the neural encoding and integration strategy of phonotactics in naturalistic conditions, when there are no (or few) violations. Here, we used linear modelling to assess the influence of phonotactic probabilities on the brain responses to narrative speech measured with non-invasive EEG. We found that the relationship between continuous speech and EEG responses is best described when the stimulus descriptor includes phonotactic probabilities. This indicates that low-frequency cortical signals (<9 Hz) reflect the integration of phonotactic information during natural speech perception, providing us with a measure of phonotactic processing at the individual subject-level. Furthermore, phonotactics-related signals showed the strongest speech-EEG interactions at latencies of 100-500 ms, supporting a pre-lexical role of phonotactic information.
人类能够理解言语，尽管存在各种挑战，例如发音错误和嘈杂的环境。我们的听觉系统具有很强的鲁棒性，可以将感官输入与基于语言规则的先验知识和期望进行整合。其中一个规则涉及允许的音素序列，这决定了一个词属于给定语言的可能性（音位规则概率；“blick”比“bnick”更有可能是英语单词）。先前的研究表明，违反这些规则会调节大脑诱发的反应。然而，仍有几个基本问题尚未解决，特别是关于在自然条件下，即没有（或很少有）违反规则的情况下，音位规则的神经编码和整合策略。在这里，我们使用线性建模来评估音位规则概率对使用非侵入性 EEG 测量的叙事言语的大脑反应的影响。我们发现，当刺激描述符包括音位规则概率时，连续言语和 EEG 反应之间的关系描述得最好。这表明低频皮质信号（<9 Hz）反映了自然言语感知过程中音位规则信息的整合，为我们提供了一种在个体受试者水平上测量音位规则处理的方法。此外，音位规则相关信号在 100-500 ms 的潜伏期显示出最强的言语-EEG 相互作用，支持音位规则信息的词汇前作用。
