Spontaneous fluctuations in the blood oxygenation level dependent signal measured through resting-state functional magnetic resonance imaging have been corroborated to aggregate into multiple functional networks. Abnormal resting brain activity is observed in mood disorder patients, however with inconsistent results. How do such alterations relate to clinical symptoms; e.g., level of depression and rumination tendencies? Here we recovered spatially and temporally overlapping functional networks from 31 mood disorder patients and healthy controls during rest, by applying novel methods that identify transient changes in spontaneous brain activity. Our unique approach disentangles the dynamic engagement of resting-state networks unconstrained by the slow hemodynamic response. This time-varying characterization provides moment-to-moment information about functional networks in terms of their durations and dynamic coupling, and offers novel evidence for selective contributions to particular clinical symptoms. Patients showed increased duration of default-mode network (DMN), increased duration and occurrence of posterior DMN as well as insula- and amygdala-centered networks, but decreased occurrence of visual and anterior salience networks. Coupling between limbic (insula and amygdala) networks was also reduced. Depression level modulated DMN duration, whereas intrusive thoughts correlated with occurrence of insula and posterior DMN. Anatomical network organization was similar to controls. In sum, altered brain dynamics in mood disorder patients appear to mediate distinct clinical dimensions including increased self-processing, and decreased attention to external world.

通过静息态功能磁共振成像测量的血氧水平相关信号的自发波动已被证实聚合成多个功能网络。在情绪障碍患者中观察到异常的静息大脑活动，但结果不一致。这些改变与临床症状有何关系？例如，抑郁程度和沉思倾向？在这里，我们通过应用识别自发大脑活动短暂变化的新方法，从 31 名情绪障碍患者和健康对照者的休息期间恢复了空间和时间重叠的功能网络。我们独特的方法解开了静息态网络的动态参与，不受缓慢的血流动力学响应的限制。这种随时间变化的特征提供了有关功能网络在持续时间和动态耦合方面的即时信息，并为 特定临床症状的选择性贡献提供了新的证据。患者表现出默认模式网络（DMN）的持续时间增加、后DMN以及以岛叶和杏仁核为中心的网络的持续时间和发生率增加，但视觉和前显着网络的发生率减少。边缘系统（岛叶和杏仁核）网络之间的耦合也减少了。抑郁水平调节 DMN 持续时间，而侵入性思维与岛叶和后 DMN 的发生相关。解剖网络组织与对照相似。总之，情绪障碍患者的大脑动力学改变似乎介导了不同的临床维度，包括自我处理能力增强和对外部世界的注意力减少。