Omissions of Threat Trigger Subjective Relief and Reward Prediction Error-Like Signaling in the Human Reward System

The unexpected absence of danger constitutes a pleasurable event that is critical for the learning of safety. Accumulating evidence points to similarities between the processing of absent threat and the well-established reward prediction error (PE). However, clear-cut evidence for this analogy in humans is scarce. In line with recent animal data, we showed that the unexpected omission of (painful) electrical stimulation triggers reward-like activations within key regions of the canonical reward pathway and that these activations correlate with the pleasantness of the reported relief. Furthermore, by parametrically violating participants’ probability and intensity related expectations of the upcoming stimulation, we showed for the first time in humans that omission-related activations in the VTA/SN were stronger following omissions of more probable and intense stimulations, like a positive reward PE signal. Together, our findings provide additional support for an overlap in the neural processing of absent danger and rewards in humans.

意外缺席的威胁构成了一个对安全学习至关重要的愉悦事件。越来越多的证据表明，对缺席威胁的处理与已确立的奖励预测误差（PE）之间存在相似性。然而，在人类中支持这种类比的确凿证据仍然稀缺。与最近动物实验数据一致，我们研究发现，意外遗漏（痛苦）的电气刺激会在经典奖励途径的关键区域引发类似奖励的激活，并且这些激活与所报告的缓解的愉悦感相关。此外，通过参数化违反参与者对即将到来的刺激的概率和强度相关预期，我们首次在人类中展示了，在遗漏更可能和更强烈的刺激（如积极奖励的PE信号）后，VTA/SN区域与遗漏相关的激活更为强烈。综上所述，我们的发现为人类中缺席危险与奖励的神经处理重叠提供了额外的支持。