Gradual extinction prevents the return of fear: implications for the discovery of state
Gradual extinction prevents the return of fear: implications for the discovery of state
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DOI：
10.3389/fnbeh.2013.00164
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发表时间：
2013-11-18
影响因子：
3
通讯作者：
Niv, Yael
中科院分区：
文献类型：
--
作者：
Gershman, Samuel J.;Jones, Carolyn E.;Niv, Yael
恐惧记忆是出了名的难以抹去，往往会随着时间的推移而恢复。对于这一发现，长期以来的解释是，在消退训练中，一种新的记忆形成了，它与旧的记忆竞争表达，但不会改变旧的记忆，这种解释与传统的学习模型（如Rescorla-Wagner和强化学习）不一致。最近提出的一个可能的和解是，灭绝训练导致了一种新状态的推断，这种新状态与原始训练中有效的状态不同。然而，这个解决方案提出了一个新的问题：新的状态或新的记忆是在什么条件下形成的？理论解释表明，在这一过程中存在持续的大预测误差。为了验证这一观点，我们推断，在消退训练中仔细设计强化时间表，可以减少这些预测错误，足以阻止新记忆的形成，同时仍然减少强化，足以驱动旧的恐惧记忆的修改。在两个巴甫洛夫恐惧条件反射实验中，我们发现逐渐减少厌恶刺激的频率，而不是突然消除它们，可以防止恐惧的恢复。这一发现对强化学习中的状态发现理论具有重要意义。
Fear memories are notoriously difficult to erase, often recovering overtime. The longstanding explanation for this finding is that, in extinction training, a new memory is formed that competes with the old one for expression but does not otherwise modify it. This explanation is at odds with traditional models of learning such as Rescorla-Wagner and reinforcement learning. A possible reconciliation that was recently suggested is that extinction training leads to the inference of a new state that is different from the state that was in effect in the original training. This solution, however, raises a new question: under what conditions are new states, or new memories formed? Theoretical accounts implicate persistent large prediction errors in this process. As a test of this idea, we reasoned that careful design of the reinforcement schedule during extinction training could reduce these prediction errors enough to prevent the formation of a new memory, while still decreasing reinforcement sufficiently to drive modification of the old fear memory. In two Pavlovian fear conditioning experiments, we show that gradually reducing the frequency of aversive stimuli, rather than eliminating them abruptly, prevents the recovery of fear. This finding has important implications for theories of state discovery in reinforcement learning.