Decision Neuroscience Laboratory, School of Psychology, UNSW Sydney, Australia.
Decision Neuroscience Laboratory, School of Psychology, UNSW Sydney, Australia.
Neurobiol Learn Mem. 2024 Nov;215:107989. doi: 10.1016/j.nlm.2024.107989. Epub 2024 Oct 5.
A stimulus that predicts the delivery of a specific food outcome can bias performance towards instrumental actions that earn that same outcome in a phenomenon known as specific Pavlovian-instrumental transfer (PIT). The precise mechanism by which the specific instrumental action is selected under these circumstances has remained elusive. The present set of experiments explored whether treatments that undermine the response-outcome (R-O) association also affect the expression of specific PIT. Consistent with previous work, in Experiment 1 we showed that specific PIT remains intact after an instrumental degradation treatment that attempted to undermine R-O associations. However, we additionally demonstrated that outcome-devaluation sensitivity also persisted after degradation, suggesting that R-O associations were impervious to the degradation treatment, and precluding any conclusions about the necessity of R-O associations for specific PIT expression. Nevertheless, given the two-lever two-outcome design of this experiment it is possible that R-O associations were indeed undermined by degradation and that the devaluation effect was driven by distinct, incidental Pavlovian lever-outcome associations. To nullify the obscuring effects of these incidental Pavlovian associations, we used a bidirectional lever for instrumental conditioning that could be pushed to the left or the right for distinct outcomes. In Experiment 2 we demonstrated that specific PIT could be observed on this bidirectional manipulandum whether the subjects were hungry or sated, consistent with the literature. The critical third Experiment used an identical design to Experiment 1 except that the two instrumental responses were made on the single bidirectional manipulanda. Here, specific PIT was intact after instrumental degradation and, crucially, we saw no evidence of outcome devaluation sensitivity in these same subjects, suggesting that the R-O associations were weakened or undermined by this treatment. We conclude that the expression of specific PIT is resistant to treatments that undermine R-O associations and disrupt value based choice, and discuss how these findings contribute to our understanding of the associative framework supporting behavioral control.
一种能预测特定食物结果的刺激可以使表现偏向于获得相同结果的工具性行为，这种现象被称为特定的巴甫洛夫-工具性转移（PIT）。在这种情况下，特定工具性行为是如何被选择的精确机制一直难以捉摸。本实验集探讨了破坏反应-结果（R-O）关联的处理是否也会影响特定 PIT 的表达。与之前的工作一致，在实验 1 中，我们表明，在试图破坏 R-O 关联的工具性退化处理后，特定的 PIT 仍然完整。然而，我们还表明，在退化后，对结果的评价敏感性仍然存在，这表明 R-O 关联不受退化处理的影响，并且排除了 R-O 关联对特定 PIT 表达的必要性的任何结论。然而，鉴于这个实验的双杠杆双结果设计，R-O 关联可能确实被退化所破坏，而贬值效应是由不同的、偶然的巴甫洛夫杠杆-结果关联驱动的。为了消除这些偶然的巴甫洛夫关联的模糊效应，我们在工具性条件作用中使用了一个双向杠杆，可以向左或向右推动以获得不同的结果。在实验 2 中，我们证明，在这种双向操作器上可以观察到特定的 PIT，无论被试是饥饿还是饱足，这与文献一致。关键的实验 3 使用了与实验 1 相同的设计，只是两个工具性反应是在单一的双向操作器上做出的。在这里，在工具性退化后，特定的 PIT 仍然完整，而且至关重要的是，我们在这些相同的被试中没有看到结果评价敏感性的证据，这表明 R-O 关联被这种处理削弱或破坏了。我们得出结论，特定 PIT 的表达对破坏 R-O 关联和破坏基于价值的选择的处理具有抗性，并且讨论了这些发现如何有助于我们对支持行为控制的关联框架的理解。
