Safety signals as instrumental reinforcers during free-operant avoidance
Safety signals as instrumental reinforcers during free-operant avoidance
复制标题
DOI：
10.1101/lm.034603.114
复制
发表时间：
2014-09-01
影响因子：
2
通讯作者：
Robbins, Trevor W.
中科院分区：
文献类型：
--
作者：
Fernando, Anushka B. P.;Urcelay, Gonzalo P.;Robbins, Trevor W.
安全信号通过预测不存在令人厌恶的事件来提供“解脱”。争论的焦点是这些信号是否也起到了辅助增强剂的作用。使用自由操作杠杆-按压回避范式进行了四个实验，其中每个按压都避免电击，然后呈现5秒的听觉安全信号。在实验1中，当在两个避免电击的杠杆之间进行选择时，老鼠优先选择产生安全信号的杠杆作为反馈，即使在省略脚击的时候也是如此。在实验2中，在用单杆进行回避训练后，去除信号导致回避反应减少，而在通常由信号表示的安全期内反应增加。这些行为变化显示了安全信号的双重条件强化和恐惧抑制特性。使用一种新的重估程序测试了支持安全信号强化特性的关联过程。在无药物消光测试的前10分钟内，在无药物消光测试中，有全身注射吗啡的经验会导致产生安全信号的回避反应增加，这一发现在实验3中用d-苯丙胺是看不到的。在实验4中，实验4重复了吗啡对安全信号的重新评估，然后进行了无药物消退测试，反应在前10分钟内没有产生信号。在没有信号的情况下，工具性回避对先前的信号重估不敏感，这表明该信号通过一种类似习惯的机制加强了自由操作型回避行为。
Safety signals provide "relief" through predicting the absence of an aversive event. At issue is whether these signals also act as instrumental reinforcers. Four experiments were conducted using a free-operant lever-press avoidance paradigm in which each press avoided shock and was followed by the presentation of a 5-sec auditory safety signal. When given a choice between two levers in Experiment 1, both avoiding shock, rats preferentially responded on the lever that produced the safety signal as feedback, even when footshock was omitted. Following avoidance training with a single lever in Experiment 2, removal of the signal led to a decrease in avoidance responses and an increase in responses during the safety period normally denoted by the signal. These behavioral changes demonstrate the dual conditioned reinforcing and fear inhibiting properties of the safety signal. The associative processes that support the reinforcing properties of a safety signal were tested using a novel revaluation procedure. Prior experience of systemic morphine during safety signal presentations resulted in an increased rate of avoidance responses to produce the safety signal during a drug-free extinction test, a finding not seen with d-amphetamine in Experiment 3. Morphine revaluation of the safety signal was repeated in Experiment 4 followed by a drug-free extinction test in which responses did not produce the signal for the first 10 min of the session. Instrumental avoidance in the absence of the signal was shown to be insensitive to prior signal revaluation, suggesting that the signal reinforces free-operant avoidance behavior through a habit-like mechanism.