Holmes Nathan M, Cai Stefanie Yuxuan, Lay Belinda Po Pyn, Watts Nicola R, Westbrook R Frederick
School of Psychology.
J Exp Psychol Anim Learn Cogn. 2014 Oct;40(4):440-56. doi: 10.1037/xan0000036. Epub 2014 Jul 7.
A series of experiments used rats to examine renewal and reinstatement of extinguished second-order conditioned fear (freezing) responses. The initial experiment demonstrated that freezing responses to a stimulus (S2) were contingent on its pairings with a second stimulus (S1) and on the prior pairings of S1 and an aversive unconditioned stimulus (US). Subsequent experiments showed that these freezing responses extinguished across S2 alone presentations, but were renewed when: S2-S1 pairings and S2 alone presentations occurred in the same context and testing of S2 occurred elsewhere; S2-S1 pairings and testing were in the same context and S2 alone presentations were elsewhere; and when S2-S1 pairings, S2 alone presentations and testing occurred in different contexts. Freezing responses to an extinguished S1 were reinstated by US alone presentations. However, these responses were not reinstated to an extinguished S2 by US or S1 alone presentations, and, conversely, freezing to a nonextinguished S2 was unaffected by extinction of S1. The results were interpreted to mean that S2-S1 pairings produced an association between S2 and the fear responses elicited by S1 and that extinction of this association is controlled by context. The failure to reinstate fear responses to S2 is discussed in terms of theories developed to explain reinstatement of S1.
一系列实验使用大鼠来检验消退的二级条件性恐惧（僵住）反应的恢复和重现。最初的实验表明，对刺激（S2）的僵住反应取决于它与第二种刺激（S1）的配对，以及S1与厌恶性无条件刺激（US）的先前配对。后续实验表明，这些僵住反应在单独呈现S2时会消退，但在以下情况下会恢复：S2 - S1配对和单独呈现S2发生在相同情境中，而对S2的测试在其他地方进行；S2 - S1配对和测试在相同情境中，而单独呈现S2在其他地方进行；以及当S2 - S1配对、单独呈现S2和测试发生在不同情境中时。对消退的S1的僵住反应通过单独呈现US得以恢复。然而，单独呈现US或S1并不能使对消退的S2的这些反应恢复，相反，对未消退的S2的僵住不受S1消退的影响。这些结果被解释为意味着S2 - S1配对在S2与S1引发的恐惧反应之间产生了一种关联，并且这种关联的消退受情境控制。关于未能恢复对S2的恐惧反应，根据为解释S1的恢复而发展的理论进行了讨论。
