人脑连接组研究:脑结构网络和脑功能网络

人脑是自然界中最复杂的系统之一,在这个系统中,多个神经元、神经元集群或者多个脑区相互连接成庞杂的结构网络,并通过相互作用完成脑的各种功能.近年来,结合基于图论的复杂网络理论,研究者们发现利用结构和扩散磁共振成像数据构建的脑结构网络以及利用脑电图/脑磁图数据和功能磁共振成像数据构建的脑功能网络具有很多重要的拓扑性质,如"小世界"属性、模块化的组织结构以及主要分布在联合皮层上的核心脑区(如楔前叶、额上回、额中回).另一方面,研究者发现许多神经精神疾病(如阿尔兹海默病和精神分裂症等)与脑结构和脑功能网络的异常的拓扑变化有关,这些研究不仅为理解神经精神疾病的病理机制提供了新视角,也可能为疾病的早期诊断和治疗评价提供脑网络影像学标记.本文以人脑结构和功能连接网络的研究为重点,介绍了人脑连接组和复杂网络理论的基本概念,并且回顾了近年来人脑结构和功能连接组的研究成果,并指出了该领域中存在的问题及未来的研究方向.

Human connectome: Structural and functional brain networks

Human brain is the most complex system in the world. Within this system, multiple neurons, neural circuits or brain regions are connected to form a complex structural network. Using graph thereotical network analysis approaches, many studies have demonstrated that the structural and functional brain networks can be constructed by electrophysiological and neuroimaging data (electroencephalography, magnetoencephalography, structural MRI, diffusion MRI and functional MRI), and that the resultant brain networks show many important topological features such as the “small-world” property, modular structure and several “core” regions in the association cortex. Moreover, there is also accumulating evidence that various neurological and psychiatric diseases (e.g., Alzheimer’s disease and schizophrenia) are associated with abnormal topological architecture in their structural and functional brain networks. These studies might offer a novel avenue to elucidate pathological mechanisms underlying these brain disorders, and to uncover an imaging-based biomarker for early diagnosis and monitoring of the diseases. In this review, we first introduce some basic concepts of the human connectome and complex network theory. Then, we move on recent studies regarding the human structural and functional brain networks. Finally, we raise several technical challenges and key issues which need to be addressed in the future.