基于癫痫患者立体脑电记录的听觉注意脑功能网络研究

In everyday life, humans are always flooded with multifarious sounds concurrently. Due to the limitations of cognitive functions, listeners usually need to extract the relevant information from noisy backgrounds quickly and accurately. A key component of this effective extraction process is auditory attention, which allocates both perceptual and cognitive resources on the processing of a target sound. However, what brain areas mediate auditory attention and how these brain regions interacted during auditory attention processing are still unclear. To investigate these questions, this project will apply invasive stereo-electroencephalogram (sEEG) recordings in the patients with refractory epilepsy. This technique provides a unique opportunity for directly obtaining electrophysiological activities in the human cortex during awake and task-relevant status. We will explore the key areas of auditory attention and further model the dynamic auditory attention network using Grainger Causality Analysis. Because the sEEG approach has high spatial and temporal resolution with high signal-to-noise ratio, the results of this project will potentially not only establish the framework of auditory attention in human brain functional mapping, but also develop a new paradigm for the clinical preoperative evaluation and localization of the auditory attention function.

日常生活中，人类会在很多情况下同时接受多种声音信息。由于认知的局限性，听者往往需要从背景中快速准确地提取出相关信息。这是一个复杂的过程，而解决这一问题的关键之一是听觉注意，也就是将知觉和认知资源更多地分配在目标声的加工中。然而，有关听觉注意涉及哪些关键脑区以及这些脑区之间如何交互还尚存在争议。本项目针对这些一问题，采用难治性癫痫患者的侵入性立体脑电记录方法，对清醒且处于任务状态的人类大脑皮层的电生理活动进行直接记录，探索人类大脑中听觉注意功能的关键区，并利用格兰杰因果分析的方法对听觉注意调控的动态时间网络进行建模。由于立体脑电记录方法具有极高的时间、空间分辨率和高信噪比，本项目的研究成果不仅有望为人类脑功能图谱研究奠定基础，还有望发展成为神经外科手术术前功能区评估的新范式。

任何心理认知过程都是建立在神经系统活动基础上的。本研究重点利用高时间、空间分辨率的颅内电生理记录技术研究听觉注意自上而下与自上而下的调节作用机制。本项目一共采集到55例癫痫患者初级听皮层、颞上回和岛叶在一般听觉功能和听觉注意任务下的神经反应，并发现岛叶后侧皮层在被动听觉的条件下有非常早期的high-gamma频段激活，且激活模式与传统听觉皮层（初级听皮层和颞上回）模式类似；岛叶作为听觉和其他高级认知功能中继站，调控初级听皮层和颞上回之间的功能环路；同时在听觉皮层和岛叶上记录到的微触点（micro-contact）的场电位信号，验证了宏触点的发现。课题组已基本完成本项目研究计划，揭示了人类被试在清醒且执行听觉一般任务与注意任务时的大脑神经元电活动，为听觉和言语加工神经机制的研究提供了独一无二的视角。