Memories are multifaceted and can simultaneously contain positive and negative attributes. Here, we report that negative attributes of a mixed-valence memory dominate long-term recall. To induce a mixed-valence memory, running responses were randomly reinforced with either food (∼83% of trials) or footshock (∼17% of trials), or a noise conditioned stimulus (CS) was followed randomly with either food (∼80% of trials) or footshock (∼20% of trials). Control animals were consistently reinforced with only food. Mixed-valence training promoted unstable behavior (e.g., erratic approach and withdrawal from the food cup) and moderate levels of fear during the training regimens. After a 20-day retention interval, animals that were consistently reinforced with food exhibited intact approach responding, and similar responding was observed if animals were food deprived or satiated (i.e., the response was insensitive to motivation). However, animals that experienced the mixed-valence training expressed significantly enhanced and stable fear (consistent immobility) relative to the end of training, regardless of whether animals were food deprived or not, suggesting that fear transitioned to a state that was insensitive to motivation. The degree of fear expressed during long-term retention was predicted by measures of state anxiety obtained prior to the training, indicating that the enhancement of fear across the retention interval was related to individual differences in basal "anxiety." These results suggest that negative attributes of memories dominate long-term recall, particularly in animals expressing an anxious phenotype, and these observations have direct implications for the chronic nature of anxiety disorders and the exacerbation of fear that accompanies posttraumatic stress disorder. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

中文翻译：

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混合价记忆的负面属性在较长的保留间隔内会增强，增强的程度可以通过状态焦虑的个体差异来预测。

记忆是多方面的，可以同时包含积极和消极的属性。在这里，我们报告混合价记忆的负面属性主导着长期回忆。为了诱导混合价记忆，跑步反应随机用食物（~83%的试验）或足部电击（~17%的试验）来强化，或者噪声条件刺激（CS）随机用任何一种食物（~80%）来强化。 % 的试验）或足部休克（∼20% 的试验）。对照动物始终仅用食物进行强化。混合价训练在训练过程中促进了不稳定的行为（例如不稳定的接近和从食物杯中撤出）和中等程度的恐惧。20天的保留间隔后，持续用食物强化的动物表现出完整的接近反应，并且如果动物被剥夺食物或饱足（即反应对动机不敏感），则观察到类似的反应。然而，与训练结束相比，经历过混合价训练的动物表现出显着增强和稳定的恐惧（持续不动），无论动物是否被剥夺食物，这表明恐惧转变为对动机不敏感的状态。长期保留期间表达的恐惧程度是通过训练前获得的状态焦虑测量来预测的，这表明在保留间隔期间恐惧的增强与基础“焦虑”的个体差异有关。这些结果表明，记忆的负面属性主导着长期回忆，特别是在表达焦虑表型的动物中，这些观察结果对焦虑症的慢性性质和伴随创伤后应激障碍的恐惧加剧有直接影响。（PsycInfo 数据库记录 (c) 2023 APA，保留所有权利）。