Reversal learning paradigms are widely-used assays of behavioral flexibility with their probabilistic versions being more amenable to studying integration of reward outcomes over time. Prior research suggests differences between initial and reversal learning, including higher learning rates, a greater need for inhibitory control, and more perseveration after reversals. However, it is not well-understood what aspects of stimulus-based reversal learning are unique to reversals, and whether and how observed differences depend on reward probability. Here, we used a visual probabilistic discrimination and reversal learning paradigm where male and female rats selected between a pair of stimuli associated with different reward probabilities. We compared accuracy, rewards collected, omissions, latencies, win-stay/lose-shift strategies, and indices of perseveration across two different reward probability schedules. We found that discrimination and reversal learning are behaviorally more unique than similar: latencies to select the better option, win-stay strategies, and perseveration were of a different pattern in reversal learning compared to discrimination learning. Additionally, fit of choice behavior using reinforcement learning models revealed a lower sensitivity to the difference in subjective reward values (greater exploration) and higher learning rates for the reversal phase. Interestingly, a consistent reward probability group difference emerged with a richer environment associated with longer reward collection latencies than a leaner environment. We also replicated previous reports on sex differences in reversal learning. Future studies should systematically compare the neural correlates of fine-grained behavioral measures to reveal possible dissociations in how the circuitry is recruited in each phase.

中文翻译：

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基于刺激的概率逆向学习的独特功能

逆向学习范式是行为灵活性的广泛使用的测定方法，其概率形式更适合于研究随着时间的推移奖励成果的整合。先前的研究表明，初始学习和逆向学习之间存在差异，包括较高的学习率，对抑制性控制的更大需求以及逆向后的坚持不懈。然而，尚不清楚基于刺激的逆向学习的哪些方面是逆向​​所独有的，以及观察到的差异是否以及如何取决于奖励概率。在这里，我们使用了视觉概率歧视和逆向学习范例，其中雄性和雌性大鼠在与不同奖励概率相关的一对刺激之间进行选择。我们比较了准确性，收集的奖励，遗漏，延迟，获胜/失败/转移策略，以及在两个不同的奖励概率计划中的毅力指数。我们发现，歧视和逆向学习在行为上比相似性更独特：与歧视性学习相比，选择更好的选择的潜伏期，获胜的策略和毅力在反向学习中的模式不同。此外，使用强化学习模型进行的选择行为拟合显示出对主观奖励值差异的敏感性较低（更大的探索），而逆向阶段的学习率较高。有趣的是，与较瘦的环境相比，与更长的奖励收集延迟相关联的更丰富的环境出现了一致的奖励概率组差异。我们还复制了以前关于逆向学习中性别差异的报告。