Department of Anatomy & Cell Biology, Schulich School of Medicine & Dentistry, London, Ontario, Canada.
J Affect Disord. 2013 Sep 25;150(3):1136-41. doi: 10.1016/j.jad.2013.05.053. Epub 2013 Jun 14.
Abnormalities in amygdala function have been implicated in major depression. However, results are inconsistent, and little is known about how the depressed brain encodes conflicting social signals. We sought to determine how the task relevance of socio-emotional cues impacts neural encoding of emotion in depression.
Eighteen medication-free depressed patients and 18 matched controls participated in an FMRI experiment. Whole-brain analyses and a region-of-interest approach was used to measure amygdala activity during the presentation of fearful, happy, or neutral target faces with congruent, incongruent, or neutral distracters.
Greater amygdala activity to target fearful faces was associated with depression, as was attenuated amygdala activity to target and peripheral happy faces. Although no group differences emerged in the amygdala to unattended fearful faces, we observed reduced ventrolateral and dorsomedial prefrontal activity in depressed individuals during this condition.
Nine patients had a history of anti-depressant use, though they were unmedicated for at least three months at testing.
Depression was associated with reduced amygdala reactivity to positive social stimuli. However, enhanced amygdala responsiveness to negative emotional cues was only observed to target (attended) expressions. The results highlight the need to further determine factors that affect emotional reactivity in depression.
杏仁核功能异常与重度抑郁症有关。然而，结果并不一致，对于抑郁大脑如何编码冲突的社会信号知之甚少。我们试图确定社会情感线索的任务相关性如何影响抑郁中的情绪的神经编码。
18 名未服用药物的抑郁症患者和 18 名匹配的对照者参加了 fMRI 实验。使用全脑分析和感兴趣区方法来测量在呈现恐惧、快乐或中性目标面孔时杏仁核的活动，同时呈现一致、不一致或中性的分心物。
对目标恐惧面孔的杏仁核活动与抑郁相关，对目标和外周快乐面孔的杏仁核活动减弱。尽管在未注意到的恐惧面孔中，杏仁核没有出现组间差异，但我们观察到抑郁个体在这种情况下的腹外侧和背内侧前额叶活动减少。
9 名患者有抗抑郁药物使用史，但在测试时至少已经停药三个月。
抑郁与对正面社会刺激的杏仁核反应性降低有关。然而，只有对目标（注意到的）表情，才观察到对负性情绪线索的杏仁核反应增强。结果强调了需要进一步确定影响抑郁中情绪反应的因素。
