Department of Communication Sciences and Disorders, University of South Carolina, Columbia, South Carolina.
Institute for Systems Research, University of Maryland, College Park, Maryland.
Hum Brain Mapp. 2019 Feb 1;40(2):663-678. doi: 10.1002/hbm.24403. Epub 2018 Sep 26.
Humans have a striking capacity to combine words into sentences that express new meanings. Previous research has identified key brain regions involved in this capacity, but little is known about the time course of activity in these regions, as hemodynamic methods such as fMRI provide little insight into temporal dynamics of neural activation. We performed an MEG experiment to elucidate the temporal dynamics of structure and content processing within four brain regions implicated by fMRI data from the same experiment: the temporo-parietal junction (TPJ), the posterior temporal lobe (PTL), the anterior temporal lobe (ATL), and the anterior inferior frontal gyrus (IFG). The TPJ showed increased activity for both structure and content near the end of the sentence, consistent with a role in incremental interpretation of event semantics. The PTL, a region not often associated with core aspects of syntax, showed a strong early effect of structure, consistent with predictive parsing models, and both structural and semantic context effects on function words. These results provide converging evidence that the PTL plays an important role in lexicalized syntactic processing. The ATL and IFG, regions traditionally associated with syntax, showed minimal effects of sentence structure. The ATL, PTL and IFG all showed effects of semantic content: increased activation for real words relative to nonwords. Our fMRI-guided MEG investigation therefore helps identify syntactic and semantic aspects of sentence comprehension in the brain in both spatial and temporal dimensions.
人类有一种惊人的能力，可以将单词组合成表达新含义的句子。先前的研究已经确定了与这种能力相关的关键大脑区域，但对于这些区域的活动时间过程知之甚少，因为 fMRI 等血流动力学方法几乎无法洞察神经激活的时间动态。我们进行了一项 MEG 实验，以阐明与同一实验的 fMRI 数据所涉及的四个大脑区域的结构和内容处理的时间动态：颞顶联合区（TPJ）、颞后区（PTL）、颞前区（ATL）和额下回前区（IFG）。TPJ 在句子接近结尾时表现出结构和内容的活动增加，与事件语义的增量解释作用一致。PTL 是一个通常与语法核心方面无关的区域，表现出强烈的早期结构效应，与预测分析模型一致，以及对功能词的结构和语义上下文效应。这些结果提供了一致的证据，表明 PTL 在词汇化句法处理中起着重要作用。传统上与语法相关的 ATL 和 IFG 区域显示出句子结构的最小影响。ATL、PTL 和 IFG 都显示出语义内容的影响：与非词相比，真实词的激活增加。因此，我们的 fMRI 引导的 MEG 研究有助于在空间和时间维度上确定大脑中句子理解的句法和语义方面。
