A Role for Locus Coeruleus in Information Processing

蓝斑在信息处理中的作用

基本信息

批准号：
8306314
负责人：
Matthew Nassar
金额：
$ 0.84万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-09-08 至 2012-11-30
项目状态：
已结题

项目摘要

Decisions often depend on representations about the probability and value of potential outcomes. However, maintaining accurate representations of these variables can be difficult in a dynamic environment. Most strategies for maintaining accurate representations in such an environment update them after experiencing unpredicted outcomes. A key challenge for these approaches is to decide how much influence that unpredicted outcomes should have on existing representations. In principle, this decision should take into account at least two forms of environmental variability. Persistent environmental stochasticity, or noise, leads each outcome to be a bad predictor of the next suggesting that each new outcome should have only a minimal influence on an existing representation. Another form of variability occurs due to sudden environmental changes, or change-points. Such change-points can render historical outcomes irrelevant to future ones, suggesting that representations should be highly influenced by a new outcome. Both forms of variability lead to deviations from expected outcomes, however the two types of variability suggest opposite courses of action. Previous work has shown that people and animals are capable of updating representations nearly optimally in noisy and changing environments, suggesting that the brain has a mechanism for using environmental variability to assign influence to new outcomes. However, little is known about the underlying neural mechanisms. One prominent hypothesis implicates the brainstem nucleus locus coeruleus (LC) in providing an uncertainty signal that can be used to adaptively adjust the influence of incoming sensory information on perceptual processing. However, this theory ¿ and its relationship to more general forms of belief updating ¿ has yet to be tested empirically. The goal of this proposal is to provide me with training on state-of-the-art experimental techniques that combine quantitative behavioral and neurophysiological measurements. This training will allow me to test the hypothesis that LC encodes key computational variables related to perceived noise and change-points that are used to assign influence to incoming information. The proposed experiments are based on behavioral and computational approaches that I developed previously in my graduate work. The first specific aim is to characterize the relationship between pupil diameter and LC activity. The second aim will test whether LC activity reflects behavioral and computational metrics of outcome influence in the same subjects while they perform a representation updating task. Together these Aims will provide new insights about the role of LC in complex, adaptive behavior.

决策通常取决于有关潜在结果的概率和价值的表示。但是，在动态环境中，保持这些变量的准确表示可能很困难。在经历了不可预测的结果后，在这种环境中保持准确表示的大多数策略会更新它们。这些方法的一个主要挑战是确定未预测的结果对现有表示形式的影响。原则上，该决定应至少考虑两种形式的环境变异性。持续的环境随机性或噪声导致每个结果是下一个结果的不良预测指标，这表明每个新结果应仅对现有表示形式产生最小的影响。由于突然的环境变化或变化点，发生了另一种可变性形式。这样的变化点可以使历史成果与未来的成果无关，这表明代表应受到新结果的高度影响。两种形式的可变性都导致与预期的结果不同，但是两种可变性表明了相反的行动方案。先前的工作表明，人们和动物能够在噪声和不断变化的环境中最佳地更新表示形式，这表明大脑具有使用环境变异性将影响分配给新结果的机制。但是，关于潜在的神经机制知之甚少。一个突出的假设实现了脑干核基因座（LC）提供的不确定性信号，该信号可用于自适应地调整传入的感觉信息对感知处理的影响。但是，这种理论及其与更通用的信念更新形式的关系尚未急切地测试。该提案的目的是为我提供有关结合定量行为和神经生理学测量的最先进的实验技术的培训。该培训将使我能够检验以下假设：LC编码与感知的噪声和变更点有关的关键计算变量，这些变量用于将影响分配给传入信息。提出的实验基于我以前在研究生工作中开发的行为和计算方法。第一个具体目的是表征瞳孔直径和LC活性之间的关系。第二个目的将测试LC活动是否反映了在同一主题执行表示更新任务的同一主题中结果影响的行为和计算指标。这些目标共同提供有关LC在复杂，适应性行为中的作用的新见解。