汉字阅读的语义神经回路及其与语音回路的协作机制

An increasing interest has focused the unifying of the cognitive and neurobiological model of language processing with mounting evidence reported in recent years. A bottleneck problem emerged out to reveal the neural circuit of semantic processing. However, the limit of alphabetic language results in this issue unresolved for a long time. Taking the advantage of systematic mapping from orthography to meaning in Chinese characters, the current project proposes to investigate the neural circuit of semantic processing and its cooperative division of labor with the neural circuit of phonological processing in reading Chinese characters. Study 1 aims to identify the function regions involved in Chinese characters reading by correlating the BOLD signal with the time series of stimulus properties. Study 2 focuses on the neural circuit of semantic processing in Chinese character reading. We first examine the neural mechanism the processing of semantic components and its influence on the processing of whole characters’ meaning, and further investigate the nature of the involving of prior semantic related brain regions in the processing of semantic components. Study 3 adapts the Dynamic Causal Model (DCM) to examine the patterns of the connectivity among regions of reading network, driven both by the stimulus properties and task demands. The expected findings will reveal the dynamic of the cooperation between the neural circuits of semantic and phonological processing. It will have significance in unifying the cognitive and neurobiological model of language processing. Also, the results will provide theoretical guidance for empirical studies and applications, such as language teaching, treatment of reading disorders and clinical diagnoses.

从联结主义神经网络的角度研究词汇阅读的大脑神经机制，需要揭示语义和语音神经回路的动态协作机制，而语义加工神经回路是探讨该问题的一个亟待解决的瓶颈问题。本项目拟通过4个fMRI实验，利用汉字表义的独特性，以形旁语义起作用的神经机制为切入点，探讨汉字阅读的语义神经回路及其与语音回路的动态协作机制。研究一利用多参数相关分析技术，识别汉字语义和语音属性相关的功能脑区；研究二集中考察形旁语义加工的大脑神经机制，深入探讨形旁语义作用的实质，揭示汉字阅读中语义加工的神经回路。研究三通过建构汉字阅读的动态因果模型，考察在刺激驱动和任务调节下，阅读相关脑区联结模式的动态变化，阐明语义和语音神经回路的动态协作机制。研究结果将从跨语言的角度，阐明阅读神经网络的内部动态机制，为联结主义理论提供神经生理方面的直接证据；并为基于脑科学的教育教学和阅读障碍矫治等实践应用提供理论依据。

本项目的三个研究系统地探讨了汉字阅读的语义神经回路及其与语音神经回路的动态协作。研究一采用多参数相关研究考察了词汇阅读的认知神经机制。在综合考虑汉字频率、部件数、笔画数、具体性、可表象性以及形旁透明度的分布情况，挑选出360个汉字作为实验材料，收集了阅读命名和语义范围判断的行为实验、ERP实验以及fMRI实验1的数据。研究二按计划完成了fMRI实验2和fMRI实验3。实验2是利用汉字形旁的独特性探讨形旁语义与整字语义加工的脑机制，成功识别出颞叶亚脑区在汉字语义加工中的功能分离。实验3使用fNIRS神经成像与TMS技术相结合，成功分离出ATL和AG脑区在词汇阅读的语义整合加工中的作用。研究三同时操纵汉字语音与语义加工，完成了2个fMRI实验(透明x一致性；可表象性x一致性)，实验结果有效识别出语音和语义加工的神经回路，通过建构汉字阅读神经网络的动态因果模型，从神经网络的角度考察了语音和语义神经回路的动态协作机制。本项目提出了跨语言普遍的阅读神经网络，并深入揭示了语义加工的神经回路及其与语音神经回路间的内部动态机制，为联结主义阅读理论提供了神经生理方面的直接证据。本项目将近红外脑功能成像技术(fNIRS)与经颅磁刺激(TMS)技术相结合，为脑功能增强的阅读学习和障碍矫治等实践应用提供了理论指导。