The Neural Representation of Reward in Working Memory

描述(申请人提供)：虽然我们对简单奖赏导向行为背后的神经机制了解很多，如条件反射，但我们对奖赏信息如何与工作记忆等执行过程相互作用知之甚少。这项奖励的目的是研究不同的奖励是如何保存在工作记忆中的，比较然后选择，以便允许高效、灵活的行为。猴子将接受训练，从两个相继提供的奖励中选择一个，中间有一个短暂的延迟。因此，猴子必须在工作记忆中持有第一个奖赏，直到第二个奖赏出现，这时它会比较两个奖赏，并选择一个作为自己的选择。我们将记录猴子执行这项任务时前额叶皮质(RFC)中单个神经元的活动。我们将检查RFC神经元是否在延迟期间保持关于奖励的信息(指示工作记忆过程)，以及这种编码是否相对抽象和灵活，这将有助于评估差异很大的奖励和目标。我们将研究比较和选择这两种奖励的神经过程，这两个过程是决策的重要组成部分。我们还将比较初级和次级增强剂在工作记忆中的作用。RFC功能障碍，特别是眶前区，与药物成瘾有关。不使用工作记忆表征交替的奖励和目标(例如戒毒)可能会阻止成瘾者对成瘾行为进行自上而下的控制，从而加剧成瘾。因此，了解决定如何在不同奖赏之间做出选择和优先顺序的神经机制，可能会让我们更清楚地了解成瘾的病理，并为旨在加强自上而下控制和降低正在康复的成瘾者复发可能性的替代治疗策略提供帮助。

DESCRIPTION (provided by applicant): While we know much about the neuronal mechanisms that underlie simple reward-directed behaviors, such as conditioning, we know very little about how reward information interacts with executive processes such as working memory. The aim of this grant is to examine how different rewards are held in working memory, compared and then selected, in order to allow efficient, flexible behavior. Monkeys will be trained to choose one of two sequentially presented rewards, separated by a brief delay. Thus, the monkey has to hold the first reward in working memory until the second reward is presented, at which point it compares the two rewards and selects one for its choice. We will record the activity of single neurons in the prefrontal cortex (RFC) while the monkey is performing this task. We will examine whether RFC neurons maintain information about the reward during the delay (indicative of working memory processes), and whether this encoding is relatively abstract and flexible which would facilitate the evaluation of widely disparate rewards and goals. We will investigate the neuronal processes that underlie the comparison and selection of the two rewards, processes which are important components of decision-making. We will also compare how primary and secondary reinforcers are held in working memory. Dysfunction of the RFC, particularly the orbitofrontal region, has been implicated in drug addiction. A failure to use working memory representations of alternate rewards and goals (such as quitting the drug) might exacerbate addiction by preventing the addict from exerting top-down control over addictive behavior. Thus, understanding the neuronal mechanisms that determine how choices and priorities are made between different rewards may provide us with a clearer understanding of the pathology of addiction, and with alternative therapeutic strategies aimed at boosting top-down control and attenuating the likelihood of relapse in the recovering addict