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。眶额皮层占据了大脑皮层的很大一部分，由许多亚区组成，但我们对它的功能组织知之甚少。此外，尽管有来自人类神经成像的证据表明VS在决策中起着重要作用，但我们并不了解在单个神经元水平上发生的计算。虽然有许多研究的神经特性的VS在啮齿动物，一直很少有工作在灵长类动物，特别是在决策方面。目前的拨款旨在确定OFC和VS的功能结构，通过记录在复杂的决策任务的性能在不同的OFC子区域和VS的神经元的活动。这项工作具有重要的临床意义。OFC和VS与选择行为受损的疾病有关，如成瘾。了解这些过程的机制可能会导致这种疾病的新疗法。我们将研究两个理论框架，这两个理论框架可能与理解OFC和VS功能组织有关。第一种理论认为，额叶是分层组织的，更抽象的信息在更前的额叶区域表示。如果这 组织延伸到OFC，我们会期望在OFC的更前面的区域中有更抽象的决策信号。然而，一个相反的理论认为，眶额皮层编码了做出特定选择所期望的特定结果。然后将此信息传递给VS，VS将这些特定的预测进行整合，以编码更一般化的抽象值信号。我们将测试这两个理论，通过操纵的抽象性的价值相关的信息在复杂的决策任务的性能，并检查这些信息在不同领域的OFC和VS的神经元编码。首先，我们将检查相对于主要神经元的二级神经元编码。次级货币，如货币，可以作为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，并研究当任务通过次级强化激发时OFC和VS如何相互作用。其次，我们将研究眶额皮层和视觉系统在两个被认为是决策基础的过程中的参与：预测一个行动的具体后果，并为每个后果赋予一个抽象的值。最后，我们将研究OFC和VS编码是否在决策的时间抽象性方面有所不同。特别是，我们的许多行为都是等级制的。在高层次作出的决定往往需要在低层次实现干预的子目标。最近的研究表明，VS可能负责编码目标的价值，而OFC负责编码实现目标所需的子目标的价值。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.