Department of Cognitive Psychology, Universität Hamburg, Von-Melle-Park 5, 20146, Hamburg, Germany.
Institute for Systems Neuroscience, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany.
Cogn Affect Behav Neurosci. 2021 Apr;21(2):372-389. doi: 10.3758/s13415-021-00874-0. Epub 2021 Feb 24.
Because threatening situations often occur in a similar manner, the generalization of fear to similar situations is adaptive and can avoid harm to the organism. However, the overgeneralization of fear to harmless stimuli is maladaptive and assumed to contribute to anxiety disorders. Thus, elucidating factors that may modulate fear (over)generalization is important. Based on the known effects of acute stress on learning, which are at least partly due to noradrenergic arousal, we investigated whether stress may promote fear overgeneralization and whether we could counteract this effect by reducing noradrenergic arousal. In a placebo-controlled, double-blind, between-subjects design, 120 healthy participants underwent a fear-conditioning procedure on Day 1. Approximately 24 hours later, participants received orally either a placebo or the beta-adrenergic receptor antagonist propranolol and were exposed to a stress or control manipulation before they completed a test of fear generalization. Skin conductance responses as well as explicit rating data showed a successful acquisition of conditioned fear on Day 1 and a pronounced fear generalization 24 hours later. Although physiological data confirmed the successful stress manipulation and reduction of noradrenergic arousal, the extent of fear generalization remained unaffected by stress and propranolol. The absence of a stress effect on fear generalization was confirmed by a second study and a Bayesian analysis across both data sets. Our findings suggest that acute stress leaves fear generalization processes intact, at least in a sample of healthy, young individuals.
由于威胁性情境常常以相似的方式出现，因此将恐惧泛化到相似情境是适应的，可以避免对机体造成伤害。然而，将恐惧过度泛化到无害刺激是适应不良的，被认为是导致焦虑障碍的原因之一。因此，阐明可能调节恐惧（过度）泛化的因素很重要。基于急性应激对学习的已知影响，这些影响至少部分归因于去甲肾上腺素的唤醒，我们研究了应激是否会促进恐惧过度泛化，以及我们是否可以通过降低去甲肾上腺素的唤醒来抵消这种影响。在一项安慰剂对照、双盲、被试间设计的研究中，120 名健康参与者在第 1 天接受了恐惧条件反射程序。大约 24 小时后，参与者口服接受安慰剂或β肾上腺素能受体拮抗剂普萘洛尔，并在完成恐惧泛化测试之前接受应激或对照操作。皮肤电反应和外显评分数据显示，第 1 天成功获得了条件恐惧，24 小时后明显出现了恐惧泛化。尽管生理数据证实了应激操作的成功和去甲肾上腺素唤醒的降低，但应激和普萘洛尔对恐惧泛化的程度均无影响。第二项研究和两个数据集的贝叶斯分析都证实了应激对恐惧泛化没有影响。我们的研究结果表明，急性应激至少在健康年轻个体的样本中不会影响恐惧泛化过程。
