Abstract: With the development of the brain imaging and the analysis methods, it is obvious that there are more and more limitations for the unimodal brain imaging or a single analysis method to be used to reveal the brain mechanisms of the major depressive disorder patients. However, instead of the use of the unimodal brain imaging or a single analysis method, the combination of the multimodal brain imaging and a variety of analysis methods might promote the exploration of the depressive brain structures and function, and could be used into the diagnosis, intervention and treatment more effectively as well. This paper firstly introduced some indexes or technologies of the multimodal brain imaging and the analysis methods briefly, such as the voxel-based morphometry (VBM) analysis, the diffusion tensor imaging (DTI) for the brain structure analysis, the functional connectivity (FC) analysis, the independent component analysis (ICA), the small world network (SWN) analysis for the brain function analysis, and the amplitude of low frequency fluctuation (ALFF) analysis and the regional homogeneity (ReHo) analysis for the brain regional activity analysis. Then, it summarized some researches about the brain structures and function in the major depressive disorder patients in the perspective of the fusion of the brain structures, the fusion of the brain function, the fusion of the brain structures and function, and the disease identification and classification based on multimodal indices. It was found that the major depressive disorder was related with abnormal structures and function of many brain regions and loops. More specifically, these brain regions are the frontal lobe area [e.g., dorsolateral prefrontal cortex (DLPFC), orbital frontal cortex (OFC), ventrolateral prefrontal cortex(VLPFC), superior frontal gyrus, inferior frontal gyrus(IFG)], the parietal lobe area (e.g., supramarginal gyrus, inferior parietal lobule), the occipital lobe area (e.g., middle occipital gyrus, cuneus, precuneus), the temporal lobe area [e.g., fusiform gyrus, superior temporal gyrus (STG)], the limbic system (e.g., amygdale, cingulate cortex, hippocampus, parahippocampal gyrus), the striatum (e.g., caudate nucleus, putamen, globus pallidus), the thalamus, the insula cortex, the cerebellum. Meanwhile, these brain circuits refer to the default mode network (DMN), the frontal-limbic circuits, the frontal-subcortical circuits and the limbic-cortico-striato-pallido-thalamic loops mainly, via the summary. And the major depressive disorder almost has an effect on the structures and the function in whole brain areas and many of the brain regions and loops play a crucial role in the cognitive and emotional processes, such as the emotional processing, the cognitive emotion regulation, the processing of the attention bias, the reward mechanism and so forth. Through the review above, combined with our previous relevant studies, we also put forward some outlook and ideas concerning the further researches in depression and other emotional disorders. For instance, the studies about the cognitive emotion regulation in the healthy or the subthreshold depression participants may contribute to the prediction of the major depressive disorder onset, as well as the researches about the major depressive disorder course, the subthreshold depression-early onset depression-current depression-remitted depression or refractory major depression, may be beneficial to the improvement of the major depressive disorder diagnosis, intervention and treatment. Last but not least, the combination of the brain imaging, the genetic studies and the molecular imaging could give assistance in our more in-depth understanding of the neurobiological basis of the major depressive disorder.

Key words: depression, brain structure, brain function, multimodal brain imaging, resting-state

摘要： 传统单一模态、单一分析方法在揭示抑郁症脑机制上存在较多局限；而新近多种模态、多种分析方法的结合可在一定程度上较好地促进对抑郁症脑功能和结构的全面探索、挖掘，可以更加有效地运用和实施于早期辅助诊断、干预治疗当中。因此，本文首先简要介绍了多种模态下的脑影像指标及其分析技术，而后分别从结构及功能神经影像数据融合等方面，概述了抑郁症脑结构和功能的研究现状，发现抑郁症患者存在诸多脑区及相关环路结构及功能的异常。同时，通过对抑郁症多模态研究现状的梳理和总结，结合我们已有的相关前期研究工作，对未来抑郁症等情感障碍的进一步研究工作提出了一些思考和展望。

关键词: 抑郁症, 脑结构, 脑功能, 多模态, 静息态