Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084.
Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084; Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084.
Physiol Behav. 2022 Nov 1;256:113938. doi: 10.1016/j.physbeh.2022.113938. Epub 2022 Aug 6.
Animals must modify their behavior based on updated expected outcomes in a changing environment. Prelimbic cortex (PrL) neural encoding during learning predicts, and is necessary for, appropriately altering behavior based on a new expected outcome value following devaluation. We aimed to determine how PrL neural activity encodes reward predictive cues after the expected outcome value of those cues is decreased following conditioned taste aversion. In one post-devaluation session, rats were tested under extinction to determine their ability to alter their behavior to the expected outcome values (i.e., extinction test). In a second post-devaluation session, rats were tested with the newly devalued outcome delivered so that the rats experienced the updated outcome value within the session (i.e., re-exposure test). We found that PrL neural encoding of the cue associated with the devalued reward predicted the ability of rats to suppress behavior in the extinction test session, but not in the re-exposure test session. While all rats were able to successfully devalue the outcome during conditioned taste aversion, a subset of rats continued to consume the devalued outcome in the re-exposure test session. We found differential patterns of PrL neural encoding in the population of rats that did not avoid the devalued outcome during the re-exposure test compared to the rats that successfully avoided the devalued outcome. Our findings suggest that PrL neural encoding dynamically tracks expected outcome values, and differential neural encoding in the PrL to reward predictive cues following expected outcome value changes may contribute to distinct behavioral phenotypes.
动物必须根据不断变化的环境中的更新预期结果来改变其行为。在学习过程中，扣带前皮质 (PrL) 的神经编码预测并为根据新的预期结果值改变行为提供必要条件，这是在价值贬损后进行的。我们旨在确定在条件性味觉厌恶后，预期结果值降低后，PrL 神经活动如何对奖励预测线索进行编码。在一个贬值后测试阶段，大鼠在消退中进行测试，以确定它们改变行为以适应预期结果值的能力（即，消退测试）。在第二个贬值后测试阶段，用新贬值的结果测试大鼠，以便大鼠在测试期间体验更新的结果值（即，重新暴露测试）。我们发现，与贬值奖励相关的线索的 PrL 神经编码预测了大鼠在消退测试阶段抑制行为的能力，但不能预测在重新暴露测试阶段的能力。虽然所有大鼠都能够成功地在条件性味觉厌恶中贬值结果，但一部分大鼠在重新暴露测试阶段继续消耗贬值结果。我们发现，在重新暴露测试阶段没有避免贬值结果的大鼠群体中的 PrL 神经编码存在差异模式，而成功避免贬值结果的大鼠则没有。我们的研究结果表明，PrL 神经编码动态跟踪预期结果值，并且在预期结果值变化后，PrL 对奖励预测线索的神经编码的差异可能导致不同的行为表型。
