Brain Science Institute, Tamagawa University, 6-1-1 Tamagawagakuen, Machida, Tokyo, 194-8610, Japan.
Division of the Humanities and Social Sciences, California Institute of Technology, 1200 E California Blvd, Pasadena, CA, 91125, USA.
Nat Commun. 2019 Aug 15;10(1):3674. doi: 10.1038/s41467-019-11334-2.
Midbrain dopamine neurons are known to encode reward prediction errors (RPE) used to update value predictions. Here, we examine whether RPE signals coded by midbrain dopamine neurons are modulated by the cost paid to obtain rewards, by recording from dopamine neurons in awake behaving monkeys during performance of an effortful saccade task. Dopamine neuron responses to cues predicting reward and to the delivery of rewards were increased after the performance of a costly action compared to a less costly action, suggesting that RPEs are enhanced following the performance of a costly action. At the behavioral level, stimulus-reward associations are learned faster after performing a costly action compared to a less costly action. Thus, information about action cost is processed in the dopamine reward system in a manner that amplifies the following dopamine RPE signal, which in turn promotes more rapid learning under situations of high cost.
中脑多巴胺神经元已知编码用于更新价值预测的奖励预测误差（RPE）。在这里，我们通过在清醒行为猴子执行费力扫视任务期间记录多巴胺神经元，检查中脑多巴胺神经元编码的 RPE 信号是否受到获得奖励所付出的成本的调节。与成本较低的动作相比，在执行成本较高的动作后，多巴胺神经元对预测奖励的线索和奖励的传递的反应增加，这表明在执行成本较高的动作后 RPE 得到了增强。在行为水平上，与执行成本较低的动作相比，在执行成本较高的动作后，刺激奖励关联的学习速度更快。因此，关于动作成本的信息以放大随后的多巴胺 RPE 信号的方式在多巴胺奖励系统中被处理，这反过来又促进了高成本情况下的更快学习。
