应用动态因果模型研究阅读神经网络中背、腹侧通路的协作机制

Exploring the neuroanatomical model of visual words reading is one of the essential theoretical issue in cognitive neuroscience of language. A consistent finding reveals dorsal and ventral route involved in reading neural network, but how they overlap and interactivities remains unclear and under controversial. Using Dynamic Casual Model (DCM) approach, current project proposes two fMRI experiments to investigate the ventral and dorsal routes and their cooperation in Chinese character reading. Experiment 1 take advantage of fMRI-RA paradigm, is designed to identify brain regions for components of reading processing. Both the GLM and DCM analysis are conducted to investigate the neural network, as well as two routes (dorsal and ventral) for Chinese character reading. Experiment 2 further manipulates the stimuli properties (semantic and phonological cues) and task demands (symbolic, semantic, phonological detection task), to test the activation and connectivity among regions of reading neural network. Further analysis develops DCM with same brain structure for different conditions, the DCM results will specify how our brain regions in the same reading network are interactivity for different types of stimuli or different processing demands. The results will support the idea of universal brain neural basis for cross languages reading. Also, the results will provide theoretical guidance for empirical studies and applications, such as language teaching, treatment of reading disorders and clinical diagnoses.

在神经网络的最新取向下，探讨阅读脑机制中背侧和腹侧通路的协作机制，是解决语言认知神经科学研究的多个理论问题共同面临的焦点。本项目拟通过两个脑功能成像(fMRI)实验，建构汉字阅读的动态因果模型(DCM)，系统地考察汉字阅读的神经网络，以及阅读网络中背侧、腹侧通路的协作机制。实验1利用快速适应实验范式(fMRI-RA)的优点，识别和考察汉字阅读涉及的认知成份所对应的功能脑区，以及脑区联结形成的神经回路，并建构汉字阅读的DCM模型；实验2进一步考察在刺激属性(语音、语义信息)和任务要求下阅读脑区的动态激活及相互作用。通过DCM模型的对比，重点探讨阅读网络的脑区联结模式的变化，尤其是背侧、腹侧通路受刺激和任务影响时的协作机制。研究结果将为揭示阅读的神经生理模型，解决语言特异性脑区激活的争论等重大理论问题提供直接的证据。同时能为语言教学、阅读障碍矫治、以及临床应用提供基础和理论指导。

词汇阅读的语言认知神经科学研究结果一致表明，阅读涉及了背侧和腹侧两条神经通路的参与激活。本项目结合汉字表义的独特性，完成了两个汉字阅读的脑功能成像(fMRI)实验。实验1利用快速适应实验范式(fMRI-RA)的优点，识别和考察汉字阅读涉及的认知成分所对应的功能脑区。实验2进一步考察在刺激属性(语音、语义信息)和任务要求下阅读脑区的动态激活及相互作用。我们在传统的GLM分析基础上，采用了多参数相关分析技术、以及ALE元分析技术。并且，建构了汉字阅读神经网络的动态因果模型(DCM)，对比不同任务态下阅读网络的脑区联结模式变化。结果发现：1)汉字阅读同样涉及了背侧和腹侧两条神经回路，具有跨语言普遍的神经网络；2)前人发现的语言特异的阅读脑区激活可能是被实验室任务夸大的结果；3)在刺激材料的驱动和特定实验任务要求下，阅读神经网络具有动态协作的机制，负责语音加工的背侧通路与负责语义加工的腹侧通路表现出动态的分工协作。