The Role of Medial Prefrontal Cortex in Context-Dependent Valuation and Decision Processes

项目摘要/摘要 复杂环境中的决策依赖于上下文敏感的过程来估计 可用的替代方案。在某种情况下有益的行动方针在以下方面可能是不利的 又一个。背景对时间和延迟因素如何影响决策具有特别显著的影响， 在不同的环境中，不同的耐心程度是受青睐的。理解规范的认知和神经 支持根据具体情况对决策过程进行校准的机制是迈向 理解精神健康状况下看似冲动或失控的决定。 腹内侧前额叶皮质(VmPFC)被认为有助于综合的、上下文敏感的估计 通过与涉及记忆、动机和时间估计的大脑系统的交互来实现主观价值。 然而，vmPFC在解剖和功能结构上的人与人之间的差异限制了我们的 有能力在对其规范作用的机械学研究中瞄准精确和有意义的皮质亚区 临床人群研究。本项目试图识别和描述个体水平的皮质 在基于价值的决策过程中参与的子区域，这些决策需要特定于事件的时间和 上下文信息。该项目是具有神经成像专业知识的研究人员之间的合作。 以及研究基于价值的决策、上下文表示和记忆的计算方法。目标1 将使用一种类似觅食的实验范式，在这种范式中，参与独特项目的价值取决于 关于以前遇到它的时间间隔的评估，无论是最近的(“新鲜的”)还是不是 最近的(成熟的)物品在不同的情况下具有更大的奖励价值。我们将使用多会话功能磁共振成像和 VmPFC优化的采集协议，可识别显示活动的特定个体皮质区域 由新近依赖的值调制，而与物理物品特征或新近本身无关。我们 假设估值效应将出现在vmPFC亚区，这些亚区在个体内和 与内侧颞叶和其他大脑结构有系统的功能连接。 目标2将开发一个认知过程的理论计算模型，以灵活地翻译插曲 将时间信息转化为决策价值。我们将根据行为数据和 将在我们自己的fMRI数据和其他现有数据集中测试模型预测的表示。目标3将 检查在哪些情况下，上下文依赖值的模式必须在 在不断变化的环境中的反馈基础，并将使用功能磁共振成像来检查与上下文相关的信号 VmPFC和内侧颞叶的更新。该项目的成果将促进我们的根本 理解复杂环境中支持情境适应性决策行为的大脑过程 并将在未来的研究中为识别有意义的皮质分析目标提供新的方法 以决策模式不适应为特征的健康状况。

PROJECT SUMMARY/ABSTRACT Decisions in complex environments rely on context-sensitive processes for estimating the subjective value of available alternatives. A course of action that would be beneficial in one context might be disadvantageous in another. Context has an especially pronounced impact on how time and delay factor into decisions, with different levels of patience favored in different environments. Understanding the normative cognitive and neural mechanisms that support context-appropriate calibration of decision processes is a critical step toward understanding the seemingly impulsive or dysregulated decisions that occur in mental health conditions. Ventromedial prefrontal cortex (vmPFC) is thought to contribute to integrative, context-sensitive estimates of subjective value via interactions with brain systems involved in memory, motivation, and time estimation. However, person-to-person variability in the anatomy and functional topography of vmPFC has limited our ability to target precise and meaningful cortical subregions in mechanistic studies of its normative role or in studies of clinical populations. The present project seeks to identify and characterize individual-level cortical subregions engaged during value-based decisions that require event-specific integration of temporal and contextual information. The project is a collaboration among investigators with expertise using neuroimaging and computational methods to study value-based decision making, context representation, and memory. Aim 1 will use a foraging-like experimental paradigm in which the value of engaging with a distinctive item depends on an episodic assessment of how recently it was previously encountered, with either recent (“fresh”) or non- recent (“ripe”) items having greater reward value in different contexts. We will use multi-session fMRI with a vmPFC-optimized acquisition protocol to identify individual-specific cortical regions that show activity modulated by recency-dependent value irrespective of physical item features or recency per se. We hypothesize that valuation effects will emerge in vmPFC subregions that are reproducible within-individual and have a systematic profile of functional connectivity with the medial temporal lobe and other brain structures. Aim 2 will develop a theoretical computational model of cognitive processes for flexibly translating episodic temporal information into decision value. We will test and refine the model on the basis of behavioral data and will test for model-predicted representations in our own fMRI data and other existing data sets. Aim 3 will examine situations in which patterns of context-dependent value must be disengaged and reinstated on the basis of feedback in a changing environment, and will use fMRI to examine signals associated with contextual updating in vmPFC and medial temporal lobes. Results from the project will advance our fundamental understanding of brain processes that support contextually adaptive decision behavior in complex environments and will lead to new methods for identifying meaningful cortical analysis targets in future studies of health conditions characterized by maladaptive patterns of decision making.