1 Department of Psychiatry, McGill University, Montreal, Canada.
2 Association of Atlantic Universities, Halifax Nova Scotia, Canada.
J Psychopharmacol. 2017 Sep;31(9):1225-1233. doi: 10.1177/0269881117711707. Epub 2017 Jun 21.
Bright light can affect mood states and social behaviours. Here, we tested potential interacting effects of light and dopamine on facial emotion recognition. Participants were 32 women with subsyndromal seasonal affective disorder tested in either a bright (3000 lux) or dim light (10 lux) environment. Each participant completed two test days, one following the ingestion of a phenylalanine/tyrosine-deficient mixture and one with a nutritionally balanced control mixture, both administered double blind in a randomised order. Approximately four hours post-ingestion participants completed a self-report measure of mood followed by a facial emotion recognition task. All testing took place between November and March when seasonal symptoms would be present. Following acute phenylalanine/tyrosine depletion (APTD), compared to the nutritionally balanced control mixture, participants in the dim light condition were more accurate at recognising sad faces, less likely to misclassify them, and faster at responding to them, effects that were independent of changes in mood. Effects of APTD on responses to sad faces in the bright light group were less consistent. There were no APTD effects on responses to other emotions, with one exception: a significant light × mixture interaction was seen for the reaction time to fear, but the pattern of effect was not predicted a priori or seen on other measures. Together, the results suggest that the processing of sad emotional stimuli might be greater when dopamine transmission is low. Bright light exposure, used for the treatment of both seasonal and non-seasonal mood disorders, might produce some of its benefits by preventing this effect.
强光会影响情绪状态和社交行为。在这里，我们测试了光和多巴胺对面部情绪识别的潜在相互作用。参与者是 32 名有亚综合征季节性情感障碍的女性，她们在强光（3000 勒克斯）或弱光（10 勒克斯）环境下接受测试。每位参与者完成两天的测试，其中一天在摄入苯丙氨酸/酪氨酸缺乏混合物后，另一天在摄入营养均衡的对照混合物后进行，这两种混合物都以双盲的随机顺序给药。摄入后大约四个小时，参与者完成了一项情绪自评，然后进行了面部情绪识别任务。所有测试都在 11 月至 3 月之间进行，因为此时会出现季节性症状。与营养均衡的对照混合物相比，在弱光环境下，接受急性苯丙氨酸/酪氨酸耗竭（APTD）的参与者在识别悲伤面孔时更准确，不太可能将其错误分类，并且对其的反应速度更快，这些影响独立于情绪变化。APTD 对强光环境下参与者对悲伤面孔反应的影响不太一致。APTD 对其他情绪的反应没有影响，但有一个例外：对恐惧的反应时间出现了显著的光×混合物相互作用，但这种效应的模式不是先验预测的，也没有出现在其他测量中。总的来说，结果表明，当多巴胺传递较低时，悲伤情绪刺激的处理可能会更大。强光暴露用于治疗季节性和非季节性情绪障碍，可能通过防止这种效应来产生一些益处。
