Department of Psychology, University of Würzburg, Würzburg, Germany.
Department of Clinical Psychology, Erasmus University of Rotterdam, Rotterdam, Netherlands.
PLoS One. 2023 Nov 7;18(11):e0289047. doi: 10.1371/journal.pone.0289047. eCollection 2023.
The experience of threat was found to result-mostly-in increased pain, however it is still unclear whether the exact opposite, namely the feeling of safety may lead to a reduction of pain. To test this hypothesis, we conducted two between-subject experiments (N = 94; N = 87), investigating whether learned safety relative to a neutral control condition can reduce pain, while threat should lead to increased pain compared to a neutral condition. Therefore, participants first underwent either threat or safety conditioning, before entering an identical test phase, where the previously conditioned threat or safety cue and a newly introduced visual cue were presented simultaneously with heat pain stimuli. Methodological changes were performed in experiment 2 to prevent safety extinction and to facilitate conditioning in the first place: We included additional verbal instructions, increased the maximum length of the ISI and raised CS-US contingency in the threat group from 50% to 75%. In addition to pain ratings and ratings of the visual cues (threat, safety, arousal, valence, and contingency), in both experiments, we collected heart rate and skin conductance. Analysis of the cue ratings during acquisition indicate successful threat and safety induction, however results of the test phase, when also heat pain was administered, demonstrate rapid safety extinction in both experiments. Results suggest rather small modulation of subjective and physiological pain responses following threat or safety cues relative to the neutral condition. However, exploratory analysis revealed reduced pain ratings in later trials of the experiment in the safety group compared to the threat group in both studies, suggesting different temporal dynamics for threat and safety learning and extinction, respectively. Perspective: The present results demonstrate the challenge to maintain safety in the presence of acute pain and suggest more research on the interaction of affective learning mechanism and pain processing.
威胁的体验被发现主要导致疼痛增加，然而，目前尚不清楚完全相反的情况，即安全感是否会导致疼痛减轻。为了检验这一假设，我们进行了两项被试间实验（N=94；N=87），研究了相对于中性对照条件，习得的安全感是否可以减轻疼痛，而威胁应该会导致疼痛比中性条件增加。因此，参与者首先经历威胁或安全条件作用，然后进入一个相同的测试阶段，在该阶段，先前条件作用的威胁或安全线索和新引入的视觉线索与热痛刺激同时呈现。在实验 2 中进行了方法学上的改变，以防止安全性消退并首先促进条件作用：我们包括了额外的口头指令，增加了 ISI 的最大长度，并将威胁组中的 CS-US 连续性从 50%提高到 75%。除了疼痛评分和视觉线索评分（威胁、安全、唤醒、效价和连续性）外，在两项实验中，我们还收集了心率和皮肤电导。在获得过程中对线索评分的分析表明成功地引起了威胁和安全感，但当也施加热痛时，测试阶段的结果表明在两项实验中均迅速发生了安全性消退。结果表明，相对于中性条件，威胁或安全线索后主观和生理疼痛反应的调节幅度较小。然而，探索性分析显示，在两项研究中，安全组在实验后期的疼痛评分均低于威胁组，这表明威胁和安全性学习和消退的时间动态不同。观点：本研究结果表明，在急性疼痛存在的情况下保持安全性面临挑战，并建议对情感学习机制与疼痛处理的相互作用进行更多研究。
