School of Biological Sciences & Medical Engineering, Southeast University, Nanjing 210096, China; Key Laboratory of Child Development and Learning Science, Southeast University, Nanjing 210096, China.
Department of Psychiatry, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing 210029, China.
Prog Neuropsychopharmacol Biol Psychiatry. 2018 Apr 20;83:76-85. doi: 10.1016/j.pnpbp.2018.01.006. Epub 2018 Jan 9.
Default mode network (DMN) has discernable involvement in the representation of negative, self-referential information in depression. Both increased and decreased resting-state functional connectivity between the anterior and posterior DMN have been observed in depression. These conflicting connectivity differences necessitated further exploration of the resting-state DMN dysfunction in depression. Hence, we investigated the time-varying dynamic interactions within the DMN via functional connectivity microstates in a sub-second level. 25 patients with depression and 25 matched healthy controls were enrolled in the MEG analysis. Spherical K-means algorithms embedded within an iterative optimization frame were applied to sliding windowed correlation matrices, resulting in sub-second alternations of two functional connectivity microstates for groups and highlighting the presence of functional variability. In the power dominant state, depressed patients showed a transient decreased pattern that reflected inter/intra-subnetwork deregulation. A supplementary negatively correlated state simultaneously presented with increased connectivity between the ventromedial prefrontal cortex (vmPFC) and the posterior cingulate cortex (PCC), two core nodes for the anterior and posterior DMN respectively. Additionally, depressed patients stayed longer in the supplementary microstate compared to healthy controls. During the time spent in the supplementary microstate, an attempt to compensate for the aberrant effect of vmPFC on PCC across DMN subnetworks was possibly made to balance the self-related processes disturbed by the dominant pattern. The functional compensation mechanism of the supplementary microstate attached to the dominant disrupted one provided a possible explanation to the existing inconsistent findings between the anterior and posterior DMN in depression.
默认模式网络（DMN）在抑郁中对消极的、自我参照的信息的表现有明显的参与。在抑郁中，前后 DMN 之间的静息状态功能连接既有增加也有减少。这些相互矛盾的连接差异需要进一步探索抑郁中静息状态 DMN 的功能障碍。因此，我们通过亚秒级的功能连接微观状态来研究 DMN 内的时变动态相互作用。 25 名抑郁症患者和 25 名匹配的健康对照组被纳入 MEG 分析。球型 K-均值算法嵌入迭代优化框架中，应用于滑动窗口相关矩阵，为组生成亚秒级的两种功能连接微观状态的交替，并突出功能可变性的存在。在功率主导状态下，抑郁患者表现出一种短暂的降低模式，反映了内/子网络的失调。同时出现了一个负相关的补充状态，表现为腹内侧前额叶皮层（vmPFC）和后扣带回皮层（PCC）之间的连接增加，这两个分别是前后 DMN 的核心节点。此外，与健康对照组相比，抑郁患者在补充微观状态中停留的时间更长。在处于补充微观状态的时间里，可能会尝试补偿 vmPFC 对 DMN 子网中 PCC 的异常影响，以平衡被主导模式扰乱的自我相关过程。补充微观状态的功能补偿机制与主导紊乱的微观状态相连，为抑郁中前后 DMN 之间的不一致发现提供了可能的解释。
