Development of a Novel Trial-by-Trial Consequence Human Delay Discounting Task

描述（由申请人提供）：延迟折扣是一种冲动行为模型，它反映了个体对较小的较早奖励的相对偏好，而不是较大的较晚奖励。因此，它模拟了药物依赖的一种基本行为：选择药物使用的即时但短暂的愉悦效果，而不是持续戒断带来的延迟但更有价值的健康和社会功能改善。延迟折扣与药物滥用之间的关系已经在人类和非人类动物实验中进行了研究。然而，人类和非人类动物延迟贴现任务是否评估相同的过程仍然值得关注。人类和非人类动物研究通常都涉及在小的即时奖励和大的延迟奖励之间进行一系列选择。然而，非人类的动物贴现任务涉及到逐个试验的结果，这需要受试者在每次选择试验中经历偶然的延迟和奖励交付。人工贴现任务通常涉及假设结果。尽管在人类研究中使用的“潜在真实奖励”方法为随机选择试验提供了实际结果，但这些结果是在整个任务完成后才产生的。因此，对于潜在的真实奖励方法，参与者的选择受到偶然结果的承诺或预期的影响，而不是在会话中直接的操作性经验，可以影响后续试验的选择行为。鉴于与药物滥用有关的大量非人类动物延迟贴现数据，拥有与非人类动物方法更密切相关的可用人类贴现方法将促进转化研究。因此，利用延迟折扣来研究药物滥用个体的冲动决策的一个重要科学步骤是开发具有逐个试验结果的评估人类折扣的方法。虽然已经开发了一些采用逐试验结果的人工贴现程序，但在拟议研究中试点的程序可能比这些现有程序具有优势，包括更短的任务持续时间，缺乏作为混淆的概率强化，以及保证数据点的确定性。由于药物滥用研究中的延迟折扣程序既涉及药物滥用个体，也涉及非药物滥用个体，因此这种新的延迟折扣程序将在可卡因依赖个体和人口统计学匹配的非药物依赖个体中发展。将对先前使用的延迟折扣条件进行扩展，包括假设的和潜在的真实奖励，以及对冲动性的问卷测量，以便与新任务进行比较。组间所有折扣措施的比较可能提供趋势，保证未来更大规模的研究将这些组与这组折扣任务进行比较。最终，该项目可为药物依赖中的冲动性研究提供有力工具，并为可卡因依赖和冲动性提供重要信息。公共卫生相关性：对可卡因依赖个体和非药物依赖对照个体的行为研究将用于开发研究药物滥用中的冲动决策的新程序。广泛的现有的行为冲动措施将进行评估，这将扩大我们的理解受损的决策与可卡因滥用有关。由于可卡因滥用导致的冲动会导致公共健康危害，包括通过冲动行为传播艾滋病毒，这项研究最终应该为可卡因的预防和治疗工作提供重要信息。

DESCRIPTION (provided by applicant): Delay discounting is a behavioral model of impulsivity that indexes an individual's relative preference for smaller sooner over larger later rewards. It therefore models a fundamental behavior in drug dependence: choosing the immediate but short-lived euphoric effects of drug use over the delayed but more valuable improvements in health and social functioning that come with sustained abstinence. The relation between delay discounting and drug abuse has been studied in both human and nonhuman animal research. However, a concern remains whether human and nonhuman animal delay discounting tasks assess the same processes. Both human and nonhuman animal studies typically involve presenting a series of choices between a small immediate reward and a larger delayed reward. However, nonhuman animal discounting tasks involve trial-by-trial consequences, which require the subject to experience contingent delays and reward delivery with every choice trial. Human discounting tasks typically involve hypothetical consequences. Although "potentially real reward" methods that have been used in human research provide actual consequences for randomly selected choice trials, those consequences are delivered after the entire task is finished. Therefore, with potentially real reward methods, participants' choices are influenced by the promise or anticipation of contingent consequences, rather than direct operant experience within the session that can influence choice behavior on subsequent trials. Given the wealth of nonhuman animal delay discounting data relevant to drug abuse, it would facilitate translational research to have available human discounting methods that are more closely related to nonhuman animal methods. Therefore, an important scientific step in using delay discounting to investigate impulsive decision making in drug abusing individuals is to develop methods for assessing discounting in humans with trial-by-trial consequences. Although a few human discounting procedures have been developed that employ trial-by-trial consequences, the procedure to be piloted in the proposed study may have advantages over these existing procedures, including shorter task duration, the lack of probabilistic reinforcement as a confound, and guaranteed determinacy of data points. Because delay discounting procedures in the study of drug abuse have involved both drug abusing individuals and non-drug abusing individuals, this novel delay discounting procedure will be developed with cocaine dependent individuals and demographically matched non-drug dependent individuals. An extended battery of previously utilized delay discounting conditions involving hypothetical and potentially real rewards, as well as a questionnaire measure of impulsivity, will be assessed for comparison with the novel task. The comparison of all discounting measures between groups may provide trends that warrant a future larger study comparing these groups with this set of discounting tasks. Ultimately, this project may provide a powerful tool in the study of impulsivity in drug dependence, and provide important information on cocaine dependence and impulsivity. PUBLIC HEALTH RELEVANCE: A behavioral study in cocaine dependent individuals and non-drug dependent control individuals will be used to develop a novel procedure for studying impulsive decision making in drug abuse. A wide range of existing behavioral impulsivity measures will be assessed that will extend our understanding of impaired decision making associated with cocaine abuse. Because impulsivity resulting from cocaine abuse is known to result in public health harms, including the spread of HIV, through impulsive behavior, this study should ultimately lead to important information for cocaine prevention and treatment efforts.