Neural Substrates of Goal-Directed Learning in the Human Brain

描述（由申请人提供）：适应性行为的一个标志是能够在环境中朝着特定的目标定向，并在追求这些目标的过程中灵活地控制行动。工具性条件反射是这种行为的最简单形式，在这种行为中，动物或人类学会执行一个动作或一系列动作，以获得奖励或避免惩罚。工具性条件反射由两个不同的成分组成：目标导向成分和习惯学习成分。在目标导向学习中，一个给定的行为和目标状态（未来的奖励或惩罚）之间形成了联系。目标导向控制下的工具性行为可以随着行动奖励偶然性的变化或目标本身的奖励价值的降低而迅速改变。在习惯学习中，情境（环境中线索的配置）和给定的动作之间建立了联系，而不编码目标本身。与目标导向的学习相反，习惯学习是不灵活的，会导致强迫性行为。一旦一个行为成为一种习惯（这发生在学习过程中），它就很容易被执行，而不管目标状态的当前值如何。该项目的目的是确定人类大脑中目标导向学习和习惯学习的神经基质，并描述目标导向行为转化为习惯的过程。这将通过使用功能性磁共振成像（fMRI）扫描人类受试者来完成，以测量在执行简单的仪器条件反射任务期间的神经反应。我们将使用特定的任务操作，跟踪学习过程中fMRI信号的变化，并将正式的计算模型应用于fMRI数据，以揭示工具条件反射中的这些不同成分。这个R 03申请是为了支持一个研究计划的初步发展，由首席研究员谁刚刚开始在教师的位置，作为一个前奏，在R 01机制下的后续应用。揭示神经机制介导的目标导向和习惯学习可能有重要的意义，了解一些行为如何成为“习惯化”-强迫和难以改变使用“意志力”，如强迫症，饮食失调，强迫性赌博和药物成瘾的情况。这项研究最终可能与开发治疗方法有关，这些治疗方法可以使习惯性或强迫性行为恢复到目标导向控制。

DESCRIPTION (provided by applicant): The ability to orient toward specific goals in the environment and control actions flexibly in pursuit of those goals is a hallmark of adaptive behavior. Instrumental conditioning is the simplest form of such behavior in which an animal or human learns to perform an action or sequence of actions in order to obtain reward or avoid punishment. Instrumental conditioning is composed of two distinct components: a goal-directed and a habit-learning component. In goal-directed learning, associations are formed between a given action and the goal-state (future reward or punishment). Instrumental behavior under goal-directed control can be altered rapidly following a change in the action-reward contingencies, or a decrease in the reward value of the goal itself. In habit learning, associations are made between the context (configuration of cues in the environment) and the given action, without encoding the goal itself. In contrast to goal-directed learning, habit learning is inflexible and leads to compulsive behavior. Once an action has become a habit (which happens over the course of learning), it is liable to be performed irrespective of the current value of the goal state. The aim of this project is to determine the neural substrates of goal-directed learning and habit learning in the human brain, and characterize the process by which a goal-directed action becomes transferred to a habit. This will be accomplished by scanning human subjects using functional magnetic resonance imaging (fMRI) to measure neural responses during performance of simple instrumental conditioning tasks. We will use specific task manipulations, track changes in fMRI signals over the course of learning, and apply formal computational models to fMRI data in order to uncover these different components in instrumental conditioning. This R03 application is to support the initial development of a research program by the principal investigator who has just started in a faculty position as a prelude to a subsequent application under the R01 mechanism. Uncovering the neural mechanisms mediating goal-directed and habit learning could have important implications for understanding how some behaviors become "habitized" - compulsive and difficult to change using "willpower", as is the case in obsessive compulsive disorders, eating disorders, compulsive gambling and drug addiction. This research could ultimately be relevant in developing treatments for such conditions in which habitized or compulsive behaviors are returned to goal-directed control.