Memory for extinction of conditioned fear is long-lasting and persists following spontaneous recovery
Memory for extinction of conditioned fear is long-lasting and persists following spontaneous recovery
复制标题
DOI：
10.1101/lm.49602
复制
发表时间：
2002-11-01
影响因子：
2
通讯作者：
Quirk, GJ
中科院分区：
文献类型：
--
作者：
Quirk, GJ
在没有电击的情况下，当声音出现时，对伴随脚震的声音的条件恐惧反应会迅速消失。记忆的消失被认为与新记忆的形成有关，而不是消除条件反射。为了证明这一点，熄灭的冻结会随着时间的推移而自动恢复。然而，目前尚不清楚消退记忆能持续多久，也不知道如果在同一天消退是否会干扰条件反射的巩固。为了解决这个问题，我们对大鼠进行了7次听觉恐惧条件反射试验，1小时后进行了20次消失试验，并在延迟0、1、2、4、6、10或14天后测试了自发性恢复。随着时间的推移，对音调的条件冻结逐渐恢复，到第10天达到100%。无消光对照表明，随着时间的推移，冻结的增加不是由于条件反射记忆的孵育。完全自发恢复表明，条件反射后1小时的消退训练不影响条件反射记忆的巩固。尽管完全恢复了冷冻，但大鼠的再灭绝率有所下降，表明灭绝记忆的持久性。这些数据支持这样一种观点，即恐惧的调节和消除是由独立的系统学习的，每个系统都能保持长期记忆。
Conditioned fear responses to a tone paired with footshock rapidly extinguish when the tone is presented in the absence of the shock. Rather than erase conditioning, extinction is thought to involve the formation of new memory. In support of this, extinguished freezing spontaneously recovers with the passage of time. It is not known, however, how long extinction memory lasts or whether extinction interferes with consolidation of conditioning if given on the same day. To address this, we gave rats 7 trials of auditory fear conditioning followed 1 h later by 20 extinction trials, and tested for spontaneous recovery after a delay of 0, 1, 2, 4, 6, 10, or 14 d. Conditioned freezing to the tone gradually recovered with time to reach 100% by day 10. No-extinction controls indicated that the increase in freezing with time was not owing to incubation of conditioning memory. Complete spontaneous recovery indicates that extinction training given 1 h after conditioning does not interfere with the consolidation of conditioning memory. Despite complete recovery of freezing, rats showed savings in their rate of re-extinction, indicating persistence of extinction memory. These data support the idea that conditioning and extinction of fear are learned by independent systems, each able to retain a long-term memory.