Division of Psychiatry, Centre for Clinical Brain Sciences, University of Edinburgh, Kennedy Tower, Royal Edinburgh Hospital, Edinburgh EH10 5HF, United Kingdom.
Division of Psychiatry, Centre for Clinical Brain Sciences, University of Edinburgh, Kennedy Tower, Royal Edinburgh Hospital, Edinburgh EH10 5HF, United Kingdom.
J Affect Disord. 2024 Apr 15;351:983-993. doi: 10.1016/j.jad.2024.01.038. Epub 2024 Jan 12.
Multiple brain imaging studies of negative emotional bias in major depressive disorder (MDD) have used images of fearful facial expressions and focused on the amygdala and the prefrontal cortex. The results have, however, been inconsistent, potentially due to small sample sizes (typically N<50). It remains unclear if any alterations are a characteristic of current depression or of past experience of depression, and whether there are MDD-related changes in effective connectivity between the two brain regions.
Activations and effective connectivity between the amygdala and dorsolateral prefrontal cortex (DLPFC) in response to fearful face stimuli were studied in a large population-based sample from Generation Scotland. Participants either had no history of MDD (N=664 in activation analyses, N=474 in connectivity analyses) or had a diagnosis of MDD during their lifetime (LMDD, N=290 in activation analyses, N=214 in connectivity analyses). The within-scanner task involved implicit facial emotion processing of neutral and fearful faces.
Compared to controls, LMDD was associated with increased activations in left amygdala (P=0.031,k=4) and left DLPFC (P=0.002,k=33), increased mean bilateral amygdala activation (β=0.0715,P=0.0314), and increased inhibition from left amygdala to left DLPFC, all in response to fearful faces contrasted to baseline. Results did not appear to be attributable to depressive illness severity or antidepressant medication status at scan time.
Most studied participants had past rather than current depression, average severity of ongoing depression symptoms was low, and a substantial proportion of participants were receiving medication. The study was not longitudinal and the participants were only assessed a single time.
LMDD is associated with hyperactivity of the amygdala and DLPFC, and with stronger amygdala to DLPFC inhibitory connectivity, all in response to fearful faces, unrelated to depression severity at scan time. These results help reduce inconsistency in past literature and suggest disruption of 'bottom-up' limbic-prefrontal effective connectivity in depression.
多项关于重度抑郁症（MDD）负性情绪偏向的脑影像学研究使用了恐惧面部表情的图像，并集中于杏仁核和前额叶皮层。然而，结果一直不一致，这可能是由于样本量较小（通常 N<50）。目前尚不清楚任何改变是当前抑郁的特征还是过去抑郁的经历，以及这两个脑区之间的有效连接是否存在与 MDD 相关的变化。
在苏格兰一代的大型人群样本中，研究了对恐惧面孔刺激的杏仁核和背外侧前额叶皮层（DLPFC）之间的激活和有效连接。参与者要么没有 MDD 病史（激活分析中 N=664，连接分析中 N=474），要么在其一生中被诊断为 MDD（LMDD，激活分析中 N=290，连接分析中 N=214）。在扫描过程中，任务涉及到对中性和恐惧面孔的内隐面部情绪处理。
与对照组相比，LMDD 与左侧杏仁核（P=0.031，k=4）和左侧 DLPFC 的激活增加（P=0.002，k=33）、双侧杏仁核激活的平均增加（β=0.0715，P=0.0314）以及左杏仁核到左 DLPFC 的抑制增加有关，所有这些都是在对恐惧面孔的反应中，与基线相比。结果似乎与扫描时的抑郁严重程度或抗抑郁药物状态无关。
大多数研究参与者过去有而非当前有抑郁症，持续抑郁症状的平均严重程度较低，且相当一部分参与者正在接受药物治疗。该研究不是纵向的，参与者只接受了一次评估。
LMDD 与杏仁核和 DLPFC 的过度活跃以及更强的杏仁核到 DLPFC 的抑制性连接有关，所有这些都是对恐惧面孔的反应，与扫描时的抑郁严重程度无关。这些结果有助于减少过去文献中的不一致，并表明在抑郁中存在“自上而下”的边缘-前额叶有效连接中断。
