大多数奖赏的获得都离不开努力的付出。在努力与奖赏的关系中，努力既作为一种成本降低奖赏价值，同时也可以提升奖赏价值，形成了努力悖论现象。我们认为，这种悖论与研究者所关注的认知加工阶段不同有关：努力降低价值主要发生在努力决策阶段或努力执行阶段，而努力增加价值可能是作为努力的一种后效机制来实现的——努力提升了后续奖赏加工的敏感性。然而，努力影响奖赏加工的后效机制目前仅停留在现象学描述和行为实验阶段，少量的认知神经科学研究也没能得到明确的结论，形成了努力与奖赏研究领域的一个理论盲点。我们拟将从奖赏系统的神经生物学模型出发，围绕认知努力如何影响后续奖赏加工，结合行为范式、ERP和fMRI技术，从基本机制、影响因素和特殊人群的角度，验证认知努力通过后效机制来增加奖赏价值的假说，弥补主流理论过分强调努力成本假说的不足，以期更加全面地理解努力与奖赏的关系，为相关精神疾病的动机缺损现象提供机制性解释。

Rewards rarely occur without effort. Regarding the relationship between effort and reward, effort can either decrease reward value as a cost or increase reward value, which constitutes the effort paradox. In our opinion, this paradox stems mainly from different cognitive-processing stages involved. Reward is devalued by effort during both effort decision-making and effort-execution stages. In contrast, effort accrues reward value as an after-effect mechanism, that is, reward sensitivity is increased after effort execution. However, the after-effect mechanism remains unclear, since it is only supported by phenomenological and behavioral evidence but not by cognitive neuroscience studies, which forms a theoretical blind spot in the relationship between effort and reward. Starting from the neural model of reward system and using a combination of behavioral, event-related potential (ERP) and functional magnetic resonance imaging (fMRI) techniques, we aim to investigate how cognitive effort affects following reward processing in terms of basic mechanism, influencing factors and special populations, in order to test the hypothesis that cognitive effort adds reward value through the after-effect mechanism. Based on this theoretical validation, we can address the theoretical deficit of the effort-as-a-cost hypothesis in influential literature to better understand the relationship between effort and reward and provide a mechanical explanation for the motivational deficits observed in relevant psychiatric diseases.