In the brain, dopamine is thought to drive reward-based learning by signaling temporal difference reward prediction errors (TD errors), a ‘teaching signal’ used to train computers. Recent studies using optogenetic manipulations have provided multiple pieces of evidence supporting that phasic dopamine signals function as TD errors. Furthermore, novel experimental results have indicated that when the current state of the environment is uncertain, dopamine neurons compute TD errors using ‘belief states’ or a probability distribution over potential states. It remains unclear how belief states are computed but emerging evidence suggests involvement of the prefrontal cortex and the hippocampus. These results refine our understanding of the role of dopamine in learning and the algorithms by which dopamine functions in the brain.

在大脑中，多巴胺被认为通过发出时间差异奖励预测错误（TD 错误）信号来推动基于奖励的学习，TD 错误是一种用于训练计算机的“教学信号”。最近使用光遗传学操作的研究提供了多个证据支持阶段性多巴胺信号作为 TD 错误起作用。此外，新的实验结果表明，当环境的当前状态不确定时，多巴胺神经元使用“信念状态”或潜在状态的概率分布来计算 TD 误差。目前尚不清楚如何计算信念状态，但新出现的证据表明前额叶皮层和海马体的参与。这些结果加深了我们对多巴胺在学习中的作用以及多巴胺在大脑中发挥作用的算法的理解。