Wise T, Marwood L, Perkins A M, Herane-Vives A, Joules R, Lythgoe D J, Luh W-M, Williams S C R, Young A H, Cleare A J, Arnone D
Centre for Affective Disorders, Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
South London and Maudsley NHS Foundation Trust, London, UK.
Transl Psychiatry. 2017 Apr 25;7(4):e1105. doi: 10.1038/tp.2017.40.
Major depression is associated with altered static functional connectivity in various brain networks, particularly the default mode network (DMN). Dynamic functional connectivity is a novel tool with little application in affective disorders to date, and holds the potential to unravel fluctuations in connectivity strength over time in major depression. We assessed stability of connectivity in major depression between the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC), key nodes in the DMN that are implicated in ruminative cognitions. Functional connectivity stability between the mPFC and PCC over the course of a resting-state functional magnetic resonance imaging (fMRI) scan was compared between medication-free patients with major depression and healthy controls matched for age, sex and handedness. We tested replicability of the results in an independent sample using multi-echo resting-state fMRI. The primary sample included 20 patients and 19 controls, while the validation sample included 19 patients and 19 controls. Greater connectivity variability was detected in major depression between mPFC and PCC. This was demonstrated in both samples indicating that the results were reliable and were not influenced by the fMRI acquisition approach used. Our results demonstrate that alterations within the DMN in major depression go beyond changes in connectivity strength and extend to reduced connectivity stability within key DMN regions. Findings were robustly replicated across two independent samples. Further research is necessary to better understand the nature of these fluctuations in connectivity and their relationship to the aetiology of major depression.
重度抑郁症与多种脑网络中静态功能连接的改变有关，尤其是默认模式网络（DMN）。动态功能连接是一种新型工具，迄今为止在情感障碍中的应用较少，并且有可能揭示重度抑郁症中连接强度随时间的波动情况。我们评估了重度抑郁症患者内侧前额叶皮质（mPFC）和后扣带回皮质（PCC）之间连接的稳定性，这两个区域是DMN中的关键节点，与反刍性认知有关。我们比较了未服药的重度抑郁症患者与年龄、性别和利手相匹配的健康对照在静息态功能磁共振成像（fMRI）扫描过程中mPFC和PCC之间的功能连接稳定性。我们使用多回波静息态fMRI在一个独立样本中测试了结果的可重复性。主要样本包括20名患者和19名对照，而验证样本包括19名患者和19名对照。在重度抑郁症患者中，mPFC和PCC之间检测到更大的连接变异性。这在两个样本中均得到证实，表明结果可靠，且不受所使用的fMRI采集方法的影响。我们的结果表明，重度抑郁症患者DMN内的改变不仅限于连接强度的变化，还扩展到关键DMN区域内连接稳定性的降低。研究结果在两个独立样本中得到了有力的重复验证。有必要进行进一步的研究，以更好地理解这些连接波动的本质及其与重度抑郁症病因的关系。
