中文摘要：

目的 利用功能磁共振技术结合比率低频振幅（fractional amplitude of low-frequency，fALFF）与功能连接（functional connectivity，FC）的方法探索抑郁症心理干预治疗早期大脑自发活动的改变以及相关的神经机制。 方法 采用引导下的意象疗法对纳入的23名抑郁症患者进行4周的心理干预治疗，并在治疗前后采集被试的磁共振数据。采用fALFF及FC的分析方法并进行基于全脑体素的统计分析。 结果 4周的干预治疗后86.9%的患者症状减轻。与健康对照比较，抑郁症患者两侧眶额叶及右侧中央旁小叶的fALFF显著升高，治疗后未降低。治疗后患者背侧前扣带回、膝下扣带的自发活动明显下降，其中背侧前扣带回与右侧背外侧前额叶、膝下扣带与左侧辅助运动区的功能连接治疗后显著增强。此外，治疗后膝下扣带fALFF值与治疗后的HDRS正相关（r=0.498，P=0.015）。 结论 心理治疗通过调节重要的节点间功能的耦合及连接来重塑情感调节环路，在此过程中前扣带回是抑郁症患者功能网络改变的核心区域，大脑网络自上而下的调节模式可能是心理治疗通路中的重要机制。

英文摘要：

Objective To determine the alterations of brain spontaneous functional connectivity （FC） and investigate the underlying neural mechanism of psychotherapy in patients with major depressive disorder （MDD） by fractional amplitude of low-frequency （fALFF） and FC in resting-state functional magnetic resonance imaging （fMRI）. Methods A total of 23 MDD patients and 20 healthy controls with matched age, sex and education were enrolled in this study for 4-week guided imagery psychotherapy. Their resting-state functional magnetic resonance data were acquired before and after the intervention. Longitudinal changes of fALFF and FC were assessed based on the whole-brain voxel. Results After 4-week psychotherapy, 86.9% of patients achieved definite remission. The MDD patients showed obvious fALFF increase in the bilateral orbitofrontal cortex and right paracentral lobule when compared with the healthy controls, and no change was seen after psychotherapy. After the treatment, the spontaneous FC was obviously reduced in the dorsal anterior cingulate cortex and subgenual cingulate cortex, and that in the dorsal anterior cingulate cortex, right dorsolateral prefrontal cortex, subgenual cingulate cortex and left supplementary motor area was significantly enhanced after the intervention. The fALFF of the subgenual cingulate cortex was positively correlated with Hamilton depression scale （HDRS） after psychotherapy （r=0.498, P=0.015）. Conclusion Psychotherapy alters the coupling and connectivity in FC of vital nodes to restore the emotional-specific network. In the process, the frontocingulate is the critical area in the functional network for MDD patients, and the top-down regulatory mode might be the key mechanism for psychotherapy.