听觉-发声系统整合的认知神经机制

Speech motor control relies on the incoordination of the processing of feedback information in the sensory system and the execution of motor commands in the vocal motor system. Recently great progress has been made in the exploration of functional neural network underlying the integration of auditory system and vocal motor system. Whether and how cognitive functions get involved in the auditory-vocal integration, however, remains unclear. There is evidence that cognitive functions such as auditory attention and working memory are related to speech perception of the auditory system. On the other hand, other studies and ours reveal that auditory system and vocal motor system are functionally connected during vocalization. According to these findings, we propose that cognitive function can influence the auditory system in speech perception, which in turn gets involved in the integration of auditory system and vocal motor system. The primary purpose of this project is to address the neurocognitive mechanisms underlying the auditory-vocal integration. In order to achieve this goal, we develop cognitive training programs of auditory pattern discrimination and digit span backwards based on auditory attention and working memory, and acoustic and neurophysiological techniques that incorporate the altered auditory feedback paradigm are used to evaluate the role of cognitive function/training on the auditory-vocal integration. By doing this research, we plan to reveal the modulatory effects of auditory attention and working memory on the auditory feedback control of vocal production and address the neural mechanisms that cognitive functions get involved in the auditory-vocal integration through their functional connection with the auditory system. This work will provide scientific reference for the development of cognitive-related speech therapy techniques to treat the motor speech disorders caused by neurological diseases.

言语运动的调控，取决于感觉系统对反馈信息的处理和发声运动系统对运动命令的执行两者之间的协调整合。听觉感知系统和发声运动系统整合的功能性神经网络研究取得了重要进展，但是认知功能在两者整合过程中的作用机制尚不明了。研究表明听觉注意和工作记忆等认知功能与听觉系统的言语感知能力密切相关，我们和他人的研究则发现听觉感知系统和发声运动系统之间存在功能性的链接。据此，我们提出认知功能可以影响听觉系统的言语感知，进而作用于听觉-发声系统的整合。本项目拟通过基于听觉注意和工作记忆的听觉模式识别和逆序数字广度认知训练方法，结合基于听觉反馈扰动技术的生物声学和神经生理学方法，研究听觉-发声系统整合的认知神经机制，阐释听觉注意和工作记忆对听觉反馈调控发声运动过程的调节作用，揭示认知功能通过听觉感知系统作用听觉-发声系统整合的神经机制，为从认知功能的角度治疗神经系统疾病引起的运动性言语障碍奠定理论基础。

本项目利用基于听觉反馈扰动的心理声学方法，结合脑电/事件相关电位、静息态磁共振成像技术，通过基于逆序数字广度和频率模式重建的工作记忆训练、声调感知的言语感知学习等多种研究范式，以正常人和帕金森氏病、颞叶癫痫患者为对象，从组间和个体水平上围绕“听觉感知-发声运动整合的认知神经机制”进行了深入系统地研究，取得了一系列原创性的高水平研究成果。1）工作记忆训练和言语感知学习能够显著言语感知能力，并且产生迁移效应，显著提高言语运动调控中听觉与运动系统的交互效率；2）选择性和分散性注意力能够显著影响言语运动调控的神经编码和行为表达，并且工作记忆能够提高言语运动中听觉偏差感知的处理效率和纠正性行为的抑制性效果，证实了言语运动调控存在一个自上而下的认知处理过程；3）帕金森氏病导致的听觉反馈过度依赖行为与其听觉和运动皮层的过度活跃有关，而颞叶癫痫的听觉反馈功能障碍则与脑功能网络连接异常和皮层活动受到抑制有关，在神经和行为水平上证实了言语运动调控障碍的疾病特异性机制；4）大脑皮层的功能连接、皮层下结构的形态以及性激素水平的周期性变化与言语运动调控的行为活动和皮层活动存在显著关联，揭示了言语运动调控存在显著个体差异的神经生物学基础。本项目执行期间，课题组在J. Neurosci.、NeuroImage、Hum. Brain Mapp.等国际权威/一流期刊上发表高水平SCI论文11篇，其中通讯作者论文10篇（IF-5>5的通讯作者论文4篇），并培养4 名博士、1名硕士和1名博士后，1名副主任医师晋升为主任医师。综上所述，本项目的各项研究内容顺利完成，实现了预期的研究目标。本项目揭示了注意力和工作记忆等认知功能影响听觉感知-发声运动整合的认知神经机制，建立了言语运动调控的病理模型，从脑结构与功能以及性激素的角度阐释了言语运动调控个体差异的神经生物学基础，为从认知训练的角度实现神经性言语运动障碍的精准康复奠定了理论基础。