School of Information Science and Engineering, Lanzhou University, Lanzhou, Gansu Province 730000, PR China.
College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang Province 310027, PR China.
Clin Neurophysiol. 2019 Nov;130(11):2096-2104. doi: 10.1016/j.clinph.2019.08.009. Epub 2019 Aug 23.
Major depressive disorder (MDD) is accompanied by abnormal changes in dynamic functional connectivity (FC) among brain regions. The aim of this study is to investigate whether the abnormalities of dynamic FC in MDD are state-dependent (related to a specific connectivity state).
We performed time-varying connectivity analysis on resting-state functional magnetic resonance imaging (rs-fMRI) of 49 MDD patients and 54 matched healthy controls (HCs). FC differences between groups in each connectivity state were analyzed and associations between disease severity and dynamics of aberrant FC were explored.
Two distinct connectivity states (i.e., weakly-connected and strongly-connected state) were identified. Compared to HCs, MDD patients were associated with increased mean dwell time and decreased FC between and within subnetworks in the weakly-connected state. Dynamics of reduced FC between cognitive control network and default mode network as well as within cognitive control network predicted individual differences in depression symptom severity.
Our findings suggested that the MDD-caused FC alterations mostly appeared in the weakly-connected state, which might contribute to clinical diagnosis of MDD.
These findings provide new perspectives for understanding the state-dependent neurophysiological mechanisms in MDD.
重度抑郁症（MDD）伴随着大脑区域间动态功能连接（FC）的异常改变。本研究旨在探讨 MDD 中动态 FC 的异常是否与状态相关（与特定的连接状态相关）。
我们对 49 名 MDD 患者和 54 名匹配的健康对照组（HCs）的静息态功能磁共振成像（rs-fMRI）进行了时变连接分析。分析了每个连接状态下组间的 FC 差异，并探讨了疾病严重程度与异常 FC 动态之间的关联。
确定了两种不同的连接状态（即弱连接状态和强连接状态）。与 HCs 相比，MDD 患者在弱连接状态下与网络间和网络内的平均停留时间增加以及 FC 降低有关。认知控制网络与默认模式网络之间以及认知控制网络内的 FC 降低的动态与抑郁症状严重程度的个体差异有关。
我们的研究结果表明，MDD 引起的 FC 改变主要出现在弱连接状态，这可能有助于 MDD 的临床诊断。
这些发现为理解 MDD 中的状态依赖神经生理机制提供了新的视角。
