Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, United Kingdom;
Max Planck University College London Centre for Computational Psychiatry and Ageing Research, London WC1B 5EH, United Kingdom.
Proc Natl Acad Sci U S A. 2017 Aug 29;114(35):E7395-E7404. doi: 10.1073/pnas.1705643114. Epub 2017 Aug 14.
Optimal decision making mandates organisms learn the relevant features of choice options. Likewise, knowing how much effort we should expend can assume paramount importance. A mesolimbic network supports reward learning, but it is unclear whether other choice features, such as effort learning, rely on this same network. Using computational fMRI, we show parallel encoding of effort and reward prediction errors (PEs) within distinct brain regions, with effort PEs expressed in dorsomedial prefrontal cortex and reward PEs in ventral striatum. We show a common mesencephalic origin for these signals evident in overlapping, but spatially dissociable, dopaminergic midbrain regions expressing both types of PE. During action anticipation, reward and effort expectations were integrated in ventral striatum, consistent with a computation of an overall net benefit of a stimulus. Thus, we show that motivationally relevant stimulus features are learned in parallel dopaminergic pathways, with formation of an integrated utility signal at choice.
最优决策要求生物体学习选择选项的相关特征。同样,了解我们应该投入多少努力可能变得至关重要。中脑边缘网络支持奖励学习,但尚不清楚其他选择特征(如努力学习)是否依赖于相同的网络。使用计算功能磁共振成像,我们在不同的大脑区域中显示了努力和奖励预测误差(PE)的并行编码,其中努力 PE 在背内侧前额叶皮层中表达,而奖励 PE 在腹侧纹状体中表达。我们表明,这些信号具有共同的中脑起源,在表达这两种类型的 PE 的重叠但空间上可分离的多巴胺能中脑区域中显而易见。在动作预期期间,奖励和努力的预期在腹侧纹状体中被整合,这与刺激的整体净收益的计算一致。因此,我们表明,与动机相关的刺激特征在并行的多巴胺能通路中被学习,在选择时形成了一个综合的效用信号。