Neurophysiology underlying neural representations of value

描述（由申请人提供）：该项目旨在阐明大脑如何在各种行为背景和学习范式中形成对即将发生的强化的预测，这是神经科学的基本目标。 该项目涉及同时获取杏仁核和 OFC 的神经生理学记录，以便人们能够了解两个大脑区域之间的关系和活动时间。 萨尔兹曼实验室最近的工作表明，杏仁核在经典条件反射过程中提供了视觉刺激的正值或负值的表示，其中感觉刺激和特定强化结果之间存在一对一的映射。 该提案涉及扩展最近的工作，现在在简单和更复杂的强化学习形式中同时检查杏仁核和眶额皮质（OFC）的相互关联的神经生理学。 杏仁核和 OFC 是神经回路的中心节点，通常被认为将感觉刺激与情感值联系起来，从而驱动适应性认知、行为和生理反应。 这些神经回路的功能障碍可能在许多精神疾病中发挥作用，例如情绪、焦虑、成瘾和其他疾病。 第一个目标是检查经典条件反射诱导的学习过程中杏仁核和 OFC 单神经元活动局部场电位 (LFP)，以了解两个大脑区域活动的生理特性和相对时序动态。 第二个目标是通过研究这些大脑区域的生理学来扩展这项工作，当具有动机意义的刺激根据其呈现的时刻到时刻的背景而具有不同的含义时。 如果杏仁核和 OFC 中的神经处理可以随着刺激的值根据上下文提示而在每次试验中发生变化而快速切换，那么这将表明快速的上下文相关机制可以促进价值表示之间的切换。 第三个目标是研究杏仁核和 OFC 中的神经元是否代表“绝对”？或？亲戚？通过使用强化物重估范式来控制条件刺激的价值，该范式操纵刺激的相对值但保持其绝对值恒定。 该任务需要整合有关任务整体背景的信息，以便判断特定刺激的相对价值。 对于第二个和第三个目标，我们假设 OFC 要么对有关刺激的上下文信息进行编码（目标 2），要么整合有关整个任务上下文的信息（目标 3），以部分帮助管理和更新价值的神经表示。 在这种情况下，OFC 将成为整合高级信息的皮质机制的一部分，以帮助控制价值的神经表征以及基于此类表征的情感过程。

DESCRIPTION (provided by applicant): This project seeks to elucidate how the brain can form predictions about impending reinforcement in a variety of behavioral contexts and learning paradigms, which is a fundamental goal in neuroscience. The project involves obtaining neurophysiological recordings in the amygdala and OFC simultaneously so that one can understand the relationship and timing of activity between the two brain areas. Recent work from the Salzman lab has shown that the amygdala provides a representation of the positive or negative value of visual stimuli during a classical conditioning procedure in which there is a one-to-one mapping between a sensory stimulus and a particular reinforcement outcome. This proposal involves extending this recent work to now examine simultaneously the interrelated neurophysiology of the amygdala and orbitofrontal cortex (OFC) during both simple and more complex forms of reinforcement learning. The amygdala and OFC are central nodes in neural circuitry commonly assumed to link sensory stimuli with affective values so as to drive adaptive cognitive, behavioral, and physiological responses. Dysfunction of these neural circuits likely plays a role in many psychiatric diseases, such as mood, anxiety, addictive and other disorders. The first aim examines amygdala and OFC single neuron activity local field potentials (LFPs) during learning induced by classical conditioning in order to understand the physiological properties and relative timing dynamics of activity in the two brain areas. The second aim extends this work by studying the physiology of these brain areas in conditions when motivationally significant stimuli have different meanings depending on the moment-to-moment context in which they are presented. If neural processing in the amygdala and OFC can switch rapidly as the value of a stimulus changes from trial to trial depending upon a contextual cue, it will indicate that rapid context-dependent mechanisms can facilitate the switching between representations of value. The third aim investigates whether neurons in the amygdala and OFC represent the ?absolute? or the ?relative? value of conditioned stimuli by using a reinforcer revaluation paradigm that manipulates the relative value of a stimulus but holds constant its absolute value. This task requires the integration of information about the overall context of the task in order to judge the relative value of a particular stimulus. For both the second and third aims, we hypothesize that OFC either encodes contextual information about a stimulus (Aim 2), or integrates information about an overall task context (Aim 3) in part to help govern and update neural representations of value. In this scenario, OFC would be part of a cortical mechanism that integrates high-level information in order to help control neural representations of value and the emotional processes that are based on such representations.