听觉噪声整合下的视觉诱发脑机接口及其跨模态神经功能连接效应研究

Aim at the needs for the rehabilitation of sensory disorders, an urgent problem of seeking an effective stimulation method should be solved. The phenomenon of “noise benefits” in human brains inspires some new ideas for neurorehabilitation between different sensory pathways. This proposal is presented to quantitatively integrate auditory noise and visual stimulation to study audiovisual brain-computer interface (BCI) and its effects on cross-modal functional interactions. Real-time BCI with neurofeedback is adopted to induce the cross-modal audiovisual stochastic resonance, and the enhancement of steady-state visual evoked responses (SSVERs) under certain noise intensity can be interpreted. Through the stimulus-noise optimization strategies, the cerebral response rules under auditory noise can be determined. On the other side, a multilayer biologically inspired neuron-like model, which is accordance with the audiovisual physiological characteristics, was proposed. Through modeling of physical visual and auditory stimuli, the neural encoding process of auditory noise on different levels of audiovisual pathways was studied. Meanwhile, with the aid of inversion optimization analysis, the spatial synchronization trend between different brain regions was analyzed. In combining the temporal correlation coefficients of specific frequency bands calculated from brain responses of audiovisual regions with the above spatial synchronization trend, the small-world graph theory is adopted to study the spatiotemporal mapping law of audiovisual synchronization under auditory noise. Finally, the changes of functional interaction effects under different noise intensities are assessed. This proposal is proposed with an attempt of revealing the coupling mechanism of audiovisual function under the stochastic resonance mechanism, and laying the foundation for neuroplasticity based rehabilitation of sensory disorders.

针对感觉功能障碍康复需求，寻求有效神经刺激手段已成为亟待解决的问题。大脑中的“噪声共振”现象启迪了跨感觉通道神经康复的新思路。本项目拟通过定量整合听觉噪声和视觉刺激的方式研究视听觉脑机接口及其跨模态神经功能连接效应。采用实时神经反馈脑机接口诱发大脑视听觉随机共振，研究不同噪声强度对稳态视觉诱发响应的增强作用，并通过刺激-噪声优化策略确定大脑在听觉噪声下的响应规律；进而构筑符合视听觉生理特性的多层神经元仿生模型，通过对视听觉物理刺激的建模，研究听觉噪声在视听觉通路不同层面上的信息编码过程，同时借助反演优化方法分析不同噪声强度下脑区间的空间同步趋势；在此基础上，基于小世界图论理论，结合大脑视听觉区域特定频带时间相关性，研究听觉噪声下视听觉同步的时空映射关系，最终得出神经功能连接效应随噪声强度的变化规律，以期揭示视听觉功能在随机共振下的耦合机制，为基于神经可塑性的感觉功能障碍康复奠定基础。

本项目重点进行听觉噪声整合下的视觉诱发脑机接口及其跨模态神经功能连接效应研究，围绕项目的核心目标，首先，研究了单纯光闪烁与振荡棋盘格运动刺激下的大脑响应，证明了振荡棋盘格运动刺激方式能够激活更大范围的功能脑区，确定了将其作为本项目中脑机接口研究的基础范式；其次，研究了单模态视觉噪声整合下的大脑响应，结果表明视觉粉红噪声与视觉白噪声形式均能使得大脑响应随着噪声强度的增加而呈现明显的倒U形随机共振现象，揭示了大脑随机共振效应的普适性；第三，进一步研究了跨视听觉模态随机共振脑机接口，研究结果也表明视觉区稳态诱发响应与听觉噪声强度之间呈显著的倒U形共振特性曲线，证明了视听觉脑区跨模态随机共振效应的存在；第四，分析了感觉噪声作用下的脑机接口疲劳性与认知负荷性，证明了整合感觉噪声的稳态运动视觉诱发方式能够极大减轻脑机接口操作过程中的认知负荷及疲劳度；第五，分析了感觉噪声作用下的视听觉脑区神经功能连接性，得出了单侧听觉噪声输入时存在该侧视听觉脑区功能连接传递的结论，从而揭示了视听觉脑区存在的时空映射关系；第六，研究了听觉噪声整合视觉刺激脑机接口范式下的视听觉脑区耦合效应，验证了视觉枕区与听觉颞区之间的强耦合效应，且该效应与听觉噪声强度呈共振关系，达到了预期的研究目标设想；在上述研究基础上，最终分析表明跨视听觉模态随机共振下的神经可塑性效果较无噪声时得到显著增强，为后续研究基于神经可塑性的感觉功能障碍神经康复技术提供了新思路。本项目在本领域权威期刊发表SCI论文3篇，EI论文3篇，申请国家发明专利7项，其中2项已获授权，项目负责人参加境外学术会议3次，项目开展期间培养硕士研究生7名，其中1人已毕业。