Department of Neurology, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310000, China; Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Sciences, Zhejiang University, Hangzhou 310027, China.
Department of Neurology, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310000, China.
Neuroimage. 2022 May 1;251:118979. doi: 10.1016/j.neuroimage.2022.118979. Epub 2022 Feb 7.
Human language is generally combinatorial: Words are combined into sentences to flexibly convey meaning. How the brain represents sentences, however, remains debated. Recently, it has been shown that delta-band cortical activity correlates with the sentential structure of speech. It remains debated, however, whether delta-band cortical tracking of sentences truly reflects mental representations of sentences or is caused by neural encoding of semantic properties of individual words. The current study investigates whether delta-band neural tracking of speech can be explained by semantic properties of individual words. Cortical activity is recorded using electroencephalography (EEG) when participants listen to sentences repeating at 1 Hz and word lists. The semantic properties of individual words, simulated using a word2vec model, predict a stronger 1 Hz response to word lists than to sentences. When listeners perform a word-monitoring task that does not require sentential processing, the 1 Hz response to word lists, however, is much weaker than the 1 Hz response to sentences, contradicting the prediction of the lexical semantics model. When listeners are explicitly asked to parse word lists into multi-word chunks, however, cortical activity can reliably track the multi-word chunks. Taken together, these results suggest that delta-band neural responses to speech cannot be fully explained by the semantic properties of single words and are potentially related to the neural representation of multi-word chunks.
单词组合成句子以灵活地传达意义。然而，大脑如何表示句子仍然存在争议。最近，已经表明，皮层的 delta 波段活动与言语的句子结构相关。然而，仍然存在争议的是，delta 波段皮层对句子的跟踪是否真正反映了句子的心理表征，还是由单个单词的语义属性的神经编码引起的。本研究调查了言语的 delta 波段神经跟踪是否可以用单个单词的语义属性来解释。当参与者以 1 Hz 的频率重复听句子和单词列表时，使用脑电图（EEG）记录皮层活动。使用 word2vec 模型模拟的单个单词的语义属性预测对单词列表的 1 Hz 反应强于对句子的 1 Hz 反应。然而，当听众执行不需要句子处理的单词监测任务时，对单词列表的 1 Hz 反应比句子的 1 Hz 反应弱得多，这与词汇语义模型的预测相矛盾。然而，当听众被明确要求将单词列表解析成多词块时，皮层活动可以可靠地跟踪多词块。总的来说，这些结果表明，言语的 delta 波段神经反应不能完全用单个单词的语义属性来解释，并且可能与多词块的神经表示有关。
