Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, USA.
Center for Depression, Anxiety and Stress Research, McLean Hospital, Belmont, USA.
Neuropsychopharmacology. 2019 Aug;44(9):1604-1612. doi: 10.1038/s41386-019-0399-3. Epub 2019 Apr 29.
Clinical depression commonly emerges in adolescence, which is also a time of developing cognitive ability and related large-scale functional brain networks implicated in depression. In depressed adults, abnormalities in the dynamic functioning of frontoinsular networks, in particular, have been observed and linked to negative rumination. Thus, network dynamics may provide new insight into teen pathophysiology. Here, adolescents (n = 45, ages 13-19) with varying severity of depressive symptoms completed a resting-state functional MRI scan. Functional networks were evaluated using co-activation pattern analysis to identify whole-brain states of spatial co-activation that recurred across participants and time. Measures included: dwell time (proportion of scan spent in that network state), persistence (volume-to-volume maintenance of a network state), and transitions (frequency of moving from state A to state B). Analyses tested associations between depression or trait rumination and dynamics of network states involving frontoinsular and default network systems. Results indicated that adolescents showing increased dwell time in, and persistence of, a frontoinsular-default network state involving insula, dorsolateral and medial prefrontal cortex, and posterior regions of default network, reported more severe symptoms of depression. Further, adolescents who transitioned more frequently between the frontoinsular-default state and a prototypical default network state reported higher depression. Increased dominance and transition frequency of frontoinsular-default network states were also associated with higher rumination, and rumination mediated the associations between network dynamics and depression. Findings support a model in which abnormal frontoinsular dynamics confer vulnerability to maladaptive introspection, which in turn contributes to symptoms of adolescent depression.
临床抑郁症通常在青少年时期出现，而这也是认知能力发展的时期，与抑郁症相关的大规模功能大脑网络也在这一时期形成。在抑郁的成年人中，观察到额岛网络动态功能的异常，特别是与消极反刍有关。因此，网络动力学可能为青少年的病理生理学提供新的见解。在这里，有不同严重程度抑郁症状的青少年（n=45，年龄 13-19 岁）完成了一项静息态功能磁共振成像扫描。使用共同激活模式分析评估功能网络，以识别在参与者和时间上反复出现的全脑状态的空间共同激活。测量包括：停留时间（在该网络状态下扫描花费的比例）、持久性（网络状态的体积到体积维持）和转换（从状态 A 到状态 B 的频率）。分析测试了抑郁或特质反刍与涉及额岛和默认网络系统的网络状态动力学之间的关联。结果表明，表现出额岛-默认网络状态停留时间增加和持久性增加的青少年，涉及岛叶、背外侧和内侧前额叶皮层以及默认网络的后区域，报告了更严重的抑郁症状。此外，在额岛-默认网络状态和典型默认网络状态之间转换更频繁的青少年报告了更高的抑郁。额岛-默认网络状态的主导地位和转换频率增加也与反刍增加有关，反刍介导了网络动力学与抑郁之间的关联。研究结果支持这样一种模式，即异常的额岛动力学易患适应不良的内省，而这反过来又导致青少年抑郁症状的出现。
