Computational Psychiatry Research, Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric Hospital, University of Zurich, 8032 Zurich, Switzerland.
Neuroscience Center Zurich; University of Zurich, 8057 Zurich, Switzerland.
Learn Mem. 2019 Apr 19;26(5):167-175. doi: 10.1101/lm.049338.119. Print 2019 May.
Threat conditioning is a common associative learning model with translational relevance. How threat-conditioned cues impact on formally unrelated instrumental behavior in humans is not well known. Such an effect is known as Pavlovian-to-instrumental transfer (PIT). While PIT with aversive primary Pavlovian reinforcers is established in nonhuman animals, this is less clear in humans, where secondary reinforcers or instructed instrumental responses are most often investigated. We modified an existing human PIT procedure to include primary reinforcers. Participants first learned to obtain (or avoid losing) appetitive instrumental reinforcement (chocolate) by appropriate approach or avoidance actions. They either had to act (Go) or to withhold an action (NoGo), and in the Go condition either to approach a reward target to collect it or to withdraw from the reward target to avoid losing it. Then they learned to associate screen color (CS) with aversive Pavlovian reinforcement (electric shock US). In the transfer phase, we conducted the instrumental task during the presence of Pavlovian CS. In a first experiment, we show that the aversive Pavlovian CS+, compared to CS-, increased response rate in Go-Withdraw trials, i.e., induce conditioned facilitation of avoidance responses. This finding was confirmed in a second and independent experiment with an increased number of Go-Withdraw trials. Notably, we observed no appreciable conditioned suppression of approach responses. Effect size to distinguish CS+/CS- in Go-Withdraw trials was = 0.42 in the confirmation sample. This would require = 37 participants to demonstrate threat learning with 80% power. Thus, the effect size is on a practically useful scale although smaller than for model-based analysis of autonomic measures. In summary, our results indicate conditioned facilitation of formally unrelated instrumental avoidance behavior in humans and provide a novel behavioral threat learning measure that requires only key presses.
威胁性条件作用是一种具有转化相关性的常见联想学习模型。威胁性条件刺激如何影响人类中与正式无关的工具性行为尚不清楚。这种效应被称为条件性恐惧反应到工具性反应的转移（PIT）。虽然在非人类动物中已经建立了使用厌恶初级条件强化物的 PIT，但在人类中这种情况不太明确，因为人类更常研究次级强化物或指令性工具性反应。我们修改了现有的人类 PIT 程序，纳入了初级强化物。参与者首先通过适当的接近或回避动作来学习获得（或避免失去）有吸引力的工具性强化物（巧克力）。他们必须采取行动（Go）或不采取行动（NoGo），在 Go 条件下，他们要么接近奖励目标以收集它，要么从奖励目标中撤回以避免失去它。然后，他们学会将屏幕颜色（CS）与厌恶的条件性刺激（US）联系起来。在转移阶段，我们在呈现条件性刺激时进行工具性任务。在第一个实验中，我们发现与条件性刺激 CS-相比，厌恶性条件性刺激 CS+增加了 Go-Withdraw 试验中的反应率，即诱导回避反应的条件性促进。在第二个和独立的实验中，随着 Go-Withdraw 试验次数的增加，这一发现得到了证实。值得注意的是，我们没有观察到对接近反应的明显条件性抑制。在确认样本中，区分 Go-Withdraw 试验中 CS+/CS-的效应大小为 = 0.42。这需要 = 37 名参与者以 80%的功率展示威胁性学习。因此，虽然与基于模型的自主测量分析相比，该效应大小较小，但它处于实用规模。总之，我们的结果表明，人类中与正式无关的工具性回避行为存在条件性促进，并提供了一种新的行为性威胁学习测量方法，该方法仅需要按键。
