The ventral striatum is believed to encode the subjective value of cost–benefit options; however, this effect has notably been absent during choices that involve physical effort. Previous work in freely moving animals has revealed opposing striatal signals, with greater response to increasing effort demands and reduced responses to rewards requiring effort. Yet, the relationship between these conflicting signals remains unknown. Using functional magnetic resonance imaging with a naturalistic maze-navigation paradigm, we identified functionally segregated regions within the ventral striatum that separately encoded effort activation, movement initiation and effort discounting of rewards. In addition, activity in regions associated with effort activation and discounting oppositely predicted striatal encoding of effort during effort-based decision-making. Our results suggest that the dorsomedial region hitherto associated with action may instead represent the cost of effort and raise fundamental questions regarding the interpretation of striatal ‘reward’ signals in the context of effort demands. This has implications for uncovering the neural architecture underlying motivated behaviour.

腹侧纹状体被认为编码了成本效益选择的主观价值；然而，在涉及体力劳动的选择中，这种效果明显不存在。以前在自由移动的动物身上的工作揭示了相反的纹状体信号，对增加的努力需求有更大的反应，对需要努力的奖励的反应减少。然而，这些相互矛盾的信号之间的关系仍然未知。使用具有自然迷宫导航范式的功能磁共振成像，我们确定了腹侧纹状体内功能隔离的区域，这些区域分别编码了努力激活、运动启动和奖励的努力折扣。此外，在基于努力的决策过程中，与努力激活和折扣相反预测的努力纹状体编码相关的区域中的活动。我们的结果表明，迄今为止与动作相关的背内侧区域可能反而代表了努力的成本，并提出了关于在努力需求的背景下对纹状体“奖励”信号的解释的基本问题。这对于揭示动机行为背后的神经结构具有重要意义。