Reinforcer efficacy: measures and neural mechanisms

强化物功效：措施和神经机制

• 批准号: 7022937
• 负责人: SUZANNE H MITCHELL
• 金额: $ 18.03万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7022937
• 关键词: behavior test; behavioral /social science research tag; biological models; dopamine; ethology; goal oriented behavior; impulsive behavior; laboratory rat; male; motivation; neuropharmacology; nicotine; perception; preference; psychopharmacology; reinforcer; substance abuse related disorder

DESCRIPTION (provided by applicant): Studies of delay discounting in humans have revealed that drug users have an exaggerated preference for small, immediate over large, delayed rewards, even when the immediate reward is substantially smaller than the delayed reward. These studies have been interpreted to mean that drug users are more impulsive than nonusers and, possibly, that drug use has altered the processes by which individuals evaluate the benefits and costs associated with rewards. These processes are believed to determine the efficacy of drug and nondrug reinforcers to control behavior. However there are costs other than delay which can cause the value of a reinforcer to be discounted. Two such costs are uncertainty and effort. Five studies are proposed to evaluate the impact of all three costs on reinforcer efficacy (delay to the receipt of a reward, uncertainty about the receipt of the reward, and the effort required to obtain the reward) using a discounting procedure that was developed by the Principal Investigator and her colleague for use with rats. The basic hypotheses are that 1) the rats that discount delayed rewards more will also discount uncertain and effortful rewards more and 2) that discounting for the three different types of cost will be similarly effected by a series of behavioral and pharmacological manipulations. Experiment 1 determines whether rats discount large, expensive rewards to similar degrees regardless of the cost type by assessing the correlation between delay discounting, uncertainty discounting and effort discounting in the same animals, and examines the impact of chronic injections of nicotine on discounting. Experiment 2 examines how the magnitude of reward affects delay, uncertainty and effort discounting. Experiment 3 determines whether preference switches from the small, cheaper reward to the large, expensive reward when a fixed cost is added to both alternatives. Experiment 4 examines whether exposure to high-reinforcer-cost conditions leads to decreases in delay, uncertainty and effort discounting. Experiment 5 investigates the role of dopamine in modulating delay, uncertainty and effort discounting. These studies will provide information about the variables taken into account when the brain evaluates reinforcer efficacy and procedures that can be used to alter reinforcer efficacy, both of which will have implications for drug abuse treatment. Further, the data collected in these studies will provide a basis for future studies, which will examine whether differences in how individuals evaluate the value of reinforcers are causally related to the initiation, progression and cessation of drug use and abuse.

描述(由申请人提供)：对人体延迟打折的研究表明，吸毒者夸大地倾向于即时的小额奖励，而不是延迟的大额奖励，即使即时奖励比延迟奖励小得多。这些研究被解读为意味着吸毒者比不吸毒者更冲动，可能是因为吸毒者改变了个人评估与奖励相关的收益和成本的过程。这些过程被认为决定了药物和非药物增强剂控制行为的效果。然而，除了延迟之外，还有其他成本可能会导致增强剂的价值打折。这样的两个代价是不确定性和努力。建议进行五项研究，以评估所有三种成本对增强剂功效的影响(收到奖励的延迟、收到奖励的不确定性以及获得奖励所需的努力)，使用由首席调查员和她的同事开发的贴现程序用于老鼠。基本假设是：1)对延迟奖励贴现更多的老鼠也会更多地贴现不确定和费力的奖励；2)对三种不同类型的成本进行贴现也同样会受到一系列行为和药物操纵的影响。实验1通过评估同一动物中延迟折扣、不确定性折扣和努力折扣之间的相关性，确定无论成本类型如何，大鼠是否对大额、昂贵的奖励进行了类似程度的折扣，并检查了长期注射尼古丁对折扣的影响。实验2考察了奖励的大小如何影响延迟、不确定性和努力折扣。实验3确定当两种选择都增加固定成本时，偏好是否从较小的、较便宜的报酬转变为较大、较贵的报酬。实验4考察了暴露在高增强剂成本条件下是否会导致延迟、不确定性和努力折扣的减少。实验5考察了多巴胺在调节延迟、不确定性和努力折扣中的作用。这些研究将提供有关大脑评估增强剂有效性时考虑的变量的信息，以及可用于改变增强剂有效性的程序，这两者都将对药物滥用治疗产生影响。此外，这些研究中收集的数据将为未来的研究提供基础，该研究将审查个人评估增强剂价值的差异是否与药物使用和滥用的开始、进展和停止存在因果关系。