Instrumental learning is regulated by two memory systems: a relatively rigid but efficient habit system and a flexible but resource-demanding goal-directed system. Previous work has demonstrated that exposure to acute stress may shift the balance between these systems toward the habitual system. In the current study, we used a 2-day outcome devaluation paradigm with a 75% reward contingency rate and altered food reward categories to replicate and extend our previous findings. Participants learned neutral stimulus-response-reward associations on the first day. On the second day, rewards were devalued by eating to satiety. Subsequently, acute stress was induced in half of the participants using the Maastricht Acute Stress Test, while the other half engaged in a nonstressful control task. Finally, relative goal-directed versus habitual behavior was evaluated in a slips-of-action phase, where more slips-of-action indicate a shift toward the habitual system. Results showed that participants successfully acquired the stimulus-response-reward associations, that devaluation was effective, and that stressed participants displayed significant increases in cortisol and blood pressure. Stress led participants to commit more slips-of-action compared with nonstressed controls. The current study extends previous work, showing that the employed paradigm and outcome devaluation procedure are boundary conditions to the stress-induced shift in instrumental responding.

中文翻译：

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急性应激后目标导向和习惯响应之间的平衡。

工具学习受两个记忆系统的调节：一个相对僵化但有效的习惯系统和一个灵活但需要资源的目标导向系统。先前的研究表明，暴露于急性压力下可能会使这些系统之间的平衡向习惯性系统转移。在当前的研究中，我们使用了2天的结果贬值范式和75％的奖励意外率，并更改了食品奖励类别来复制和扩展我们以前的发现。参加者在第一天就学会了中性的刺激-反应-奖励关联。第二天，饱食使奖励贬值。随后，使用马斯特里赫特急性压力测试在一半的参与者中引起了急性压力，而另一半则进行了无压力的控制任务。最后，在行动清单阶段评估相对目标导向与习惯行为之间的关系，其中更多的行动清单表明向习惯系统的转变。结果表明，参与者成功地获得了刺激-反应-回报的关联，贬值是有效的，并且压力过大的参与者显示出皮质醇和血压显着增加。与无压力的对照相比，压力导致参与者做出更多的动作。当前的研究扩展了以前的工作，表明所采用的范式和成果贬值程序是仪器响应中压力引起的转变的边界条件。结果表明，参与者成功地获得了刺激-反应-回报的关联，贬值是有效的，并且压力过大的参与者显示出皮质醇和血压显着增加。与无压力的对照相比，压力导致参与者做出更多的动作。当前的研究扩展了以前的工作，表明所采用的范式和成果贬值程序是仪器响应中压力引起的转变的边界条件。结果表明，参与者成功地获得了刺激-反应-奖励的联系，贬值是有效的，并且有压力的参与者表现出皮质醇和血压的显着增加。与无压力的对照相比，压力导致参与者做出更多的动作。当前的研究扩展了以前的工作，表明所采用的范式和成果贬值程序是仪器响应中压力引起的转变的边界条件。