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到来的强化的预测，这是神经科学的基本目标。 该项目涉及同时获得杏仁核和眶额皮层的神经生理记录，以便人们可以了解这两个大脑区域之间的关系和活动时间。 Salzman实验室最近的工作表明，在经典条件反射过程中，杏仁核提供了视觉刺激的正或负值的表征，其中感官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，现在同时检查杏仁核和眶额皮层（OFC）在简单和更复杂形式的强化学习过程中相互关联的神经生理学。 杏仁核和眶额皮层是神经回路中的中心节点，通常被认为将感官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。 第一个目的是研究杏仁核和OFC单神经元活动的局部场电位（LFPs）在经典条件反射诱导的学习过程中，以了解在两个大脑区域的活动的生理特性和相对时序动力学。 第二个目标扩展了这项工作，通过研究这些大脑区域的生理条件时，动机显着的刺激有不同的意义，这取决于他们提出的时刻到时刻的背景。 如果杏仁核和眶额皮层的神经处理可以随着刺激值的变化而快速切换，这将表明快速的上下文依赖机制可以促进价值表征之间的切换。 第三个目标是研究杏仁核和眶额皮层中的神经元是否代表？绝对？还是亲戚？条件刺激的价值，通过使用一个操纵刺激的相对值，但保持其绝对值不变的重复重估范式。 这项任务需要整合有关任务整体背景的信息，以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要么编码上下文信息的刺激（目标2），或整合信息的整体任务上下文（目标3）的一部分，以帮助管理和更新神经表征的价值。 在这种情况下，眶额皮层可能是皮层机制的一部分，它整合了高级信息，以帮助控制价值的神经表征和基于这种表征的情感过程。

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.