Functional Architecture of Oribitofrontal Cortex

描述(由申请人提供)：眼眶前额叶皮质(OFC)和腹侧纹状体(VS)与决策和选择行为密切相关。OFC在大脑皮层占有很大的面积，由许多亚区组成，但我们对其功能组织知之甚少。此外，尽管有来自人类神经成像的证据表明，VS在决策过程中发挥着重要作用，但我们并不理解在单个神经元水平上进行的计算。虽然有许多关于啮齿类动物VS神经元特性的研究，但在灵长类动物中的研究还很少，特别是在决策方面。目前的资助旨在通过记录OFC和VS在复杂决策任务执行过程中不同亚区和VS的神经元活动来确定OFC和VS的功能结构。这项工作具有重要的临床意义。OFC和VS与成瘾等涉及选择行为受损的障碍有关。了解这些过程背后的机制可能会导致对这种疾病的新疗法。我们将考察两个理论框架，这两个框架可能与理解OFC和VS职能组织相关。第一种理论认为，额叶是按等级组织的，更抽象的信息出现在更前额叶区域。如果这个 随着组织延伸到OFC，我们预计OFC更前面的区域会有更多抽象的决策信号。然而，一种相反的理论是，OFC编码了做出特定选择所预期的特定结果。然后，该信息被传递给VS，VS集成这些特定的预测，以便编码更通用、更抽象的值信号。我们将通过操纵复杂决策任务执行过程中与价值相关的信息的抽象性，并研究这些信息在OFC和VS的不同区域的神经元编码来检验这两个理论。首先，我们将研究次级增强子相对于初级增强子的编码。次要的增强物，如货币，可以被用作抽象的价值衡量标准。我们将研究OFC更前部的神经元是否更有可能编码次级强化，以及当任务通过次级强化激发时，OFC和VS是如何相互作用的。其次，我们将考察OFC和VS在两个过程中的参与，这两个过程被认为是决策的基础：预测一个行动的具体结果，并为每个结果分配一个抽象值。最后，我们将检查OFC和VS编码是否与决策的时间抽象性有关。特别是，我们的很多行为都是等级制的。在层次结构的较高级别作出的决策通常需要在层次结构的较低级别实现介入性的子目标。最近的研究表明，VS可能负责编码目标的值，而OFC负责编码实现目标所必需的子目标的值。我们将使用分层选择任务来测试这一点。

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.