Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA.
Nat Neurosci. 2017 Mar 29;20(4):505-512. doi: 10.1038/nn.4506.
Reinforcement learning (RL) is the behavioral process of learning the values of actions and objects. Most models of RL assume that the dopaminergic prediction error signal drives plasticity in frontal-striatal circuits. The striatum then encodes value representations that drive decision processes. However, the amygdala has also been shown to play an important role in forming Pavlovian stimulus-outcome associations. These Pavlovian associations can drive motivated behavior via the amygdala projections to the ventral striatum or the ventral tegmental area. The amygdala may, therefore, play a central role in RL. Here we compare the contributions of the amygdala and the striatum to RL and show that both the amygdala and striatum learn and represent expected values in RL tasks. Furthermore, value representations in the striatum may be inherited, to some extent, from the amygdala. The striatum may, therefore, play less of a primary role in learning stimulus-outcome associations in RL than previously suggested.
强化学习（RL）是学习行为和对象值的行为过程。大多数 RL 模型假设多巴胺预测误差信号驱动额纹状体系电路的可塑性。然后，纹状体对驱动决策过程的值表示进行编码。然而，杏仁核在形成条件刺激-反应关联方面也被证明具有重要作用。这些条件刺激-反应关联可以通过杏仁核投射到腹侧纹状体或腹侧被盖区来驱动动机行为。因此，杏仁核可能在 RL 中发挥核心作用。在这里，我们比较了杏仁核和纹状体对 RL 的贡献，并表明杏仁核和纹状体都在 RL 任务中学习和表示预期值。此外，纹状体中的价值表示在某种程度上可能是从杏仁核继承而来的。因此，与之前的建议相比，纹状体在 RL 中学习刺激-反应关联的主要作用可能较小。
