Labrenz Franziska, Icenhour Adriane, Benson Sven, Elsenbruch Sigrid
Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University of Duisburg-Essen Essen, Germany.
Front Behav Neurosci. 2015 Nov 27;9:318. doi: 10.3389/fnbeh.2015.00318. eCollection 2015.
As a fundamental learning process, fear conditioning promotes the formation of associations between predictive cues and biologically significant signals. In its application to pain, conditioning may provide important insight into mechanisms underlying pain-related fear, although knowledge especially in interoceptive pain paradigms remains scarce. Furthermore, while the influence of contingency awareness on excitatory learning is subject of ongoing debate, its role in pain-related acquisition is poorly understood and essentially unknown regarding extinction as inhibitory learning. Therefore, we addressed the impact of contingency awareness on learned emotional responses to pain- and safety-predictive cues in a combined dataset of two pain-related conditioning studies. In total, 75 healthy participants underwent differential fear acquisition, during which rectal distensions as interoceptive unconditioned stimuli (US) were repeatedly paired with a predictive visual cue (conditioned stimulus; CS(+)) while another cue (CS(-)) was presented unpaired. During extinction, both CS were presented without US. CS valence, indicating learned emotional responses, and CS-US contingencies were assessed on visual analog scales (VAS). Based on an integrative measure of contingency accuracy, a median-split was performed to compare groups with low vs. high contingency accuracy regarding learned emotional responses. To investigate predictive value of contingency accuracy, regression analyses were conducted. Highly accurate individuals revealed more pronounced negative emotional responses to CS(+) and increased positive responses to CS(-) when compared to participants with low contingency accuracy. Following extinction, highly accurate individuals had fully extinguished pain-predictive cue properties, while exhibiting persistent positive emotional responses to safety signals. In contrast, individuals with low accuracy revealed equally positive emotional responses to both, CS(+) and CS(-). Contingency accuracy predicted variance in the formation of positive responses to safety cues while no predictive value was found for danger cues following acquisition and for neither cue following extinction. Our findings underscore specific roles of learned danger and safety in pain-related acquisition and extinction. Contingency accuracy appears to distinctly impact learned emotional responses to safety and danger cues, supporting aversive learning to occur independently from CS-US awareness. The interplay of cognitive and emotional factors in shaping excitatory and inhibitory pain-related learning may contribute to altered pain processing, underscoring its clinical relevance in chronic pain.
作为一种基本的学习过程，恐惧条件作用促进了预测性线索与具有生物学意义的信号之间关联的形成。在其应用于疼痛方面，条件作用可能为与疼痛相关的恐惧背后的机制提供重要见解，尽管尤其是在内感受性疼痛范式方面的知识仍然匮乏。此外，虽然意外性意识对兴奋性学习的影响仍在持续争论中，但其在与疼痛相关的习得中的作用却知之甚少，而关于消退作为抑制性学习，其作用基本上未知。因此，我们在两项与疼痛相关的条件作用研究的合并数据集中，探讨了意外性意识对习得的对疼痛和安全预测性线索的情绪反应的影响。总共75名健康参与者接受了差异恐惧习得，在此期间，直肠扩张作为内感受性无条件刺激（US）与预测性视觉线索（条件刺激；CS(+)）反复配对，而另一个线索（CS(-)）未配对呈现。在消退过程中，两个CS均在无US的情况下呈现。通过视觉模拟量表（VAS）评估表明习得情绪反应的CS效价以及CS-US意外性。基于意外性准确性的综合测量，进行中位数分割以比较在习得情绪反应方面意外性准确性低与高的组。为了研究意外性准确性的预测价值，进行了回归分析。与意外性准确性低的参与者相比，高度准确的个体对CS(+)表现出更明显的负面情绪反应，对CS(-)的积极反应增加。在消退后，高度准确的个体已完全消除了疼痛预测性线索的属性，同时对安全信号表现出持续的积极情绪反应。相比之下，准确性低的个体对CS(+)和CS(-)都表现出同样积极的情绪反应。意外性准确性预测了对安全线索的积极反应形成中的方差，而在习得后对危险线索以及消退后对任何线索均未发现预测价值。我们的研究结果强调了习得的危险和安全在与疼痛相关的习得和消退中的特定作用。意外性准确性似乎明显影响对安全和危险线索的习得情绪反应，支持厌恶学习独立于CS-US意识而发生。认知和情绪因素在塑造兴奋性和抑制性疼痛相关学习中的相互作用可能导致疼痛处理的改变，强调了其在慢性疼痛中的临床相关性。
