The neural underpinnings of shared meaning between speakers and listeners of naturalistic language

Speakers and listeners usually interact in larger discourses than single words or even single sentences. The goal of the present study was to identify the neural bases reflecting how the mental representation of the situation denoted in a multi-sentence discourse (situation model) is constructed and shared between speakers and listeners. An fMRI study using a variant of the ambiguous text paradigm was designed. Speakers (n=15) produced ambiguous texts in the scanner and listeners (n=27) subsequently listened to these texts in different states of ambiguity: preceded by a highly informative, intermediately informative or no title at all. Conventional BOLD activation analyses in listeners, as well as inter-subject correlation analyses between the speakers’ and the listeners’ hemodynamic time courses were performed. Critically, only the processing of disambiguated, coherent discourse with an intelligible situation model representation involved (shared) activation in bilateral lateral parietal and medial prefrontal regions. This shared spatiotemporal pattern of brain activation between the speaker and the listener suggests that the process of memory retrieval in medial prefrontal regions and the binding of retrieved information in the lateral parietal cortex constitutes a core mechanism underlying the communication of complex conceptual representations.

言语交流中的说话者与听者，其互动往往发生在远超单个单词乃至单句的大型语篇之中。本研究旨在阐明多句语篇所指代情境的心理表征（situation model）如何在双方之间构建与共享的神经基础。本研究设计了一项基于歧义文本范式（ambiguous text paradigm）变体的功能磁共振成像（fMRI，functional magnetic resonance imaging）实验：15名被试作为说话者，在扫描仪内生成歧义文本；随后27名被试作为听者，在三种歧义语境下聆听这些文本，聆听前分别配有高信息量标题、中等信息量标题，或完全无标题。研究对听者组实施了常规的血氧水平依赖（BOLD，blood oxygen level-dependent）激活分析，并针对说话者与听者的血液动力学时间序列开展了跨被试相关分析。关键结果表明，仅当处理带有可理解情境模型表征的消歧连贯语篇时，双侧外侧顶叶与内侧前额叶区域才会出现共享脑激活。说话者与听者之间这种共享的脑激活时空模式提示：内侧前额叶区域的记忆提取过程，与外侧顶叶皮层对提取信息的绑定操作，共同构成了支撑复杂概念表征交流的核心机制。