Functional Architecture of Oribitofrontal Cortex

描述（由申请人提供）：眶额皮质（OFC）和腹侧纹状体（VS）与决策和选择行为密切相关。OFC占据了大脑皮层的很大一部分，包括许多子区域，但我们对其功能组织知之甚少。此外，尽管有来自人类神经影像学的证据表明VS在决策中起着重要作用，但我们不了解在单个神经元水平上发生的计算。虽然有很多关于啮齿动物VS神经元特性的研究，但在灵长类动物中，特别是在决策方面的研究很少。目前的拨款旨在通过记录不同OFC子区域和VS的神经元在执行复杂决策任务期间的活动来确定OFC和VS的功能结构。这项工作具有重要的临床意义。OFC和VS与选择行为受损的障碍有关，比如成瘾。了解这些过程背后的机制可能会导致治疗这些疾病的新方法。我们将研究两个可能与理解OFC和VS功能组织相关的理论框架。第一种理论认为，额叶是分层组织的，更多的抽象信息集中在更多的额叶前部区域。如果这

DESCRIPTION (provided by applicant): The orbitofrontal cortex (OFC) and ventral striatum (VS) are strongly implicated in decision-making and choice behavior. OFC occupies a large extent of cortex and comprises many subareas, but we have little idea of its functional organization. In addition, although there is evidence from human neuroimaging that VS plays a significant role in decision-making, we do not understand the computations that are taking place at the single neuron level. Although there are many studies of the neuronal properties of VS in rodents, there has been little work in primates, particularly with respect to decision-making. The current grant aims to determine the functional architecture of OFC and VS by recording the activity of neurons in different OFC subregions and VS during the performance of sophisticated decision-making tasks. This work has important clinical relevance. OFC and VS have been implicated in disorders involving impaired choice behavior, such as addiction. Understanding the mechanisms underlying these processes could lead to novel treatments for such disorders. We will examine two theoretical frameworks that are potentially of relevance to understanding OFC and VS functional organization. The first theory argues that the frontal lobe is organized hierarchically with more abstract information represented in more anterior frontal regions. If this organization extends to OFC, we would expect more abstract decision-making signals in more anterior areas of OFC. However, a contrary theory is that OFC encodes the specific outcome expected from making a specific choice. This information is then passed to VS, which integrates these specific predictions in order to encode a more generalized, abstract value signal. We will test these two theories by manipulating the abstractness of value-related information during the performance of complex decision-making tasks, and examining the neuronal encoding of this information in different areas of OFC and VS. First, we will examine the encoding of secondary reinforcers relative to primary reinforcers. Secondary reinforcers, such as money, can be used as abstract measures of value. We will examine whether neurons in more anterior parts of OFC are more likely to encode secondary reinforcers and examine how OFC and VS interact when a task is motivated via secondary reinforcement. Second, we will examine the involvement of OFC and VS in two processes thought to underlie decision-making: predicting the specific consequences of an action and assigning an abstract value to each of those consequences. Finally, we will examine whether OFC and VS encoding differs in relation to the temporal abstractness of decisions. In particular, much of our behavior is hierarchical. Decisions made at high levels of the hierarchy often require the attainment of intervening subgoals at lower levels of the hierarchy. Recent work has suggested that VS may be responsible for encoding the value of the goal and OFC responsible for encoding the value of subgoals necessary to attain the goal. We will test this using a hierarchical choice task.