How to spend it: the neural basis of budget effects on cost-benefitdecisions of rodent and human consumers

在经济学中，对个体选择的实证研究大多基于人口样本的实地数据。尽管神经经济学领域取得了重大进展，但我们对经济选择的神经基础仍然知之甚少。此前的研究表明，经济学理论很好地解释了动物的行为。这些动物模型是探索微观经济学基本原理的一种手段，也是人类研究不可或缺的补充，因为它允许使用神经生物学操作。因此，建立跨物种研究将使我们能够充分理解经济行为背后的神经过程。为此，我进行了一系列损毁实验，以探索老鼠消费者的神经供需机制。老鼠被训练用努力(即戳鼻子)来换取奖励：它们对首选奖励的需求随着价格(即获得奖励所需的戳鼻子次数)的增加而减少，这表现为价格对需求弹性的影响。当预算(即每期可用鼻子戳的总次数)被延长以补偿价格上涨时，动物保持其原有的消费模式，表现为相对于价格上涨得不到补偿的情况，价格弹性较小。这种预算效应意味着，老鼠不仅根据其名义价值(例如，获得奖励所需的净努力)来评估努力成本，而且还根据其购买力(例如，根据其价格和可用的预算可以购买多少奖励)来评估努力成本。有趣的是，我已经证明，当前扣带回(ACC)受损时，预算对价格弹性的影响减弱，这表明该区域对于动物将预算信息整合到成本效益计算中至关重要。为了评估我们的任务的相对价值，我将我们的动物范式转换为人类预算任务，并表明努力和预算的操纵对人类消费者行为也有类似的影响。然而，尽管有这些发现，仍然不清楚1)预算对成本依赖的奖励价值的影响是如何在大鼠ACC神经元中表现的，2)这种预算效应背后的行为/认知过程是否跨物种平行。为了解决这些问题，我建议在执行努力预算任务的大鼠的ACC中进行四极管记录。在第二个实验中，我计划改进我们的人类任务，开发一个完全可比较的范例，允许未来在物种之间进行比较，超越行为层面。这两个实验的结果将为解释啮齿动物和人类在预算约束下基于努力的成本效益决策提供新的见解和实证证据，这在以前的研究中没有被捕获，并促进我们对经济需求理论在不同物种之间的适用性的理解。

In economics, empirical studies of individual choices are mostly based on field data from samples of human population. Despite significant advances in the field of neuroeconomics, we still know very little about the neural basis of economic choice. Previous studies showed that economic theory accounts well for animal behaviors. These animal models serve as a means to probe elementary principles of microeconomics, as well as an indispensable complement to human research by allowing neurobiological manipulations to be employed. Thus, establishing cross-species research will enable us to fully understand the neural process underlying economic behaviors. To this end, I conducted a series of lesion experiments to explore the neural mechanisms of supply and demand in rat consumers. Rats were trained to trade effort (i.e. nose poking) for rewards: their demand for preferred reward decreased as its price (i.e. number of nose pokes required to get a reward) increased, which is expressed as price effect on demand elasticity. When the budget (i.e. total number of nose pokes available per session) was extended to compensate price increases, animals maintained their original consumption pattern, as shown by smaller price elasticities relative to conditions in which price increase was not compensated. This budget effect implies that rats evaluate effort costs not only by their nominal value (e.g. net effort required to obtain a reward), but also with respect to their purchasing power (e.g., how much reward can be purchased given its price and available budget). Interestingly, I have shown that budget effect on price elasticity was diminished when anterior cingulate cortex (ACC) was damaged, suggesting this region is crucial for animals to integrate budget information into cost-benefit computations. To assess the comparative value of our task, I translated our animal paradigm to a human budget task, and showed that manipulations of effort and budget had similar effects on human consumer behavior. However, despite these findings, it is still unclear 1) how the budget effect on cost-dependent reward valuation is represented in rat ACC neurons, 2) whether behavioral/cognitive process underlying this budget effect is parallel across species. To address these issues, I propose to conduct tetrode recordings in the ACC of rats performing the effort-budget task. In the second experiment, I plan to refine our human task to develop a fully comparable paradigm that allows future comparisons between species, moving beyond the behavioral level. Results of the two experiments will provide new insights and empirical evidence to interpret effort-based cost-benefit decisions under budget constraint in rodents and humans, which are not captured in previous studies, and advance our understanding of the applicability of economic demand theory across species.