Liu Zhe, Reiner Robert, Loewenstein Yonatan, Lottem Eran
Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; Alexander Silberman Institute of Life Sciences, Department of Cognitive and Brain Sciences and The Federmann Center for the Study of Rationality, The Hebrew University of Jerusalem, Jerusalem, Israel.
Biol Psychiatry. 2025 Jun 15;97(12):1186-1194. doi: 10.1016/j.biopsych.2024.09.017. Epub 2024 Sep 28.
Impulse control is a critical aspect of cognitive functioning. Intuitively, whether an action is executed prematurely depends on its associated reward, yet the link between value and impulsivity remains poorly understood. Three frameworks for impulsivity offer contrasting views: impulsive behavior may be valuable because it is associated with hidden internal reward (e.g., reduction of mental effort). Alternatively, it can emerge from exploration, which is disadvantageous in the short term but can yield long-term benefits. Finally, impulsivity may reflect Pavlovian bias, an inherent tendency that occurs even when its outcome is negative.
To test these hypotheses, we trained 17 male mice to withhold licking while anticipating variable rewards. We then measured and optogenetically manipulated dopamine release in the ventral striatum.
We found that higher reward magnitudes correlated with increased impulsivity. This behavior was well explained by a Pavlovian bias model. Furthermore, we observed negative dopamine signals during premature licking, suggesting that in this task, impulsivity is not merely an unsuccessful attempt at obtaining a reward. Rather, it is a failure to overcome the urge to act prematurely despite knowledge of the negative consequences of such impulsive actions.
Our findings underscore the integral role value plays in regulating impulsivity and suggest that the dopaminergic system influences impulsivity through the mediation of value learning.
冲动控制是认知功能的一个关键方面。直观地说，一个动作是否过早执行取决于其相关的奖励，然而价值与冲动性之间的联系仍知之甚少。关于冲动性的三个框架提供了不同的观点：冲动行为可能是有价值的，因为它与隐藏的内在奖励相关（例如，减少心理努力）。或者，它可能源于探索，这在短期内是不利的，但可以产生长期利益。最后，冲动性可能反映巴甫洛夫偏差，即一种即使结果是负面的也会出现的固有倾向。
为了检验这些假设，我们训练了17只雄性小鼠在预期不同奖励时抑制舔舐行为。然后我们测量并通过光遗传学方法操纵腹侧纹状体中的多巴胺释放。
我们发现更高的奖励幅度与更高的冲动性相关。这种行为可以用巴甫洛夫偏差模型很好地解释。此外，我们在过早舔舐期间观察到负多巴胺信号，这表明在这项任务中，冲动性不仅仅是获取奖励的一次不成功尝试。相反，尽管知道这种冲动行为的负面后果，但仍未能克服过早行动的冲动。
我们的研究结果强调了价值在调节冲动性中所起的不可或缺的作用，并表明多巴胺能系统通过价值学习的介导影响冲动性。
