Oscillatory Measures of Number and Precision in Working Memory

描述(申请人提供)：视觉工作记忆(WM)是一种中央认知系统，用于维持对环境中物体的积极表征，以便它们可以被操纵或作用。在健康人群中，工作记忆能力的个体差异似乎反映了一种核心认知能力，因为它们强烈地预测了一个人的液态智力以及学习成绩的几个方面。此外，WM缺陷是许多普遍存在的精神健康障碍的标志。因此，如果我们要了解和治疗涉及认知障碍的精神病理，如注意力缺陷/多动障碍(ADHD)或精神分裂症，对这个系统的详细了解是必不可少的。此外，由于在线视觉记忆和基本视觉感知过程之间的紧密联系，我们的工作将有助于整合视觉感觉加工的基本知识(例如，对简单视觉特征的群体编码)和在线记忆。WM最基本的属性之一是它的容量非常有限：一次只能存储关于几个对象的信息，每个对象的精度都是有限的。最近的一个关键发现是，这些数量和精度限制是WM容量的不同方面。然而，这两个决定能力的因素背后的神经机制目前还不清楚。在这里，我们正在开发神经振荡和血流动力学测量方法，能够跟踪受试者之间和受试者内部这些能力的变化。具体地说，我们的初步数据显示，WM中持有的项目的数量是在逐个试验的基础上通过阿尔法功率(8-12赫兹)的去同步来索引的，而WM的精度是通过感觉种群代码的离散性(通过对fMRI和EEG数据的新型多变量分析来量化)来索引的。这项拟议的研究将使用心理物理学、功能磁共振成像和脑电来测量WM中跟踪数量和精度的神经信号。这些努力将为视觉的功能细分提供新的见解 Wm，并在具有良好特征的在线记忆能力的行为测量和人类振荡活动的测量之间建立了明确的桥梁。最后，我们还将研究视觉WM和视觉长期记忆(LTM)之间的相互作用，以确定WM的内容如何决定哪些内容被编码到LTM中。这些研究将有助于表征视觉工作记忆在联想学习中的作用，并阐明每个系统在复杂行为指导中的作用。通过更准确地了解健康个体在工作记忆能力和视觉感觉功能方面的差异，我们希望开发出方法和程序，可以用于更准确地检测和表征精神健康障碍人群的疾病状态，并诊断和量化视觉引导行为中的障碍。

DESCRIPTION (provided by applicant): Visual working memory (WM) is a central cognitive system for maintaining active representations about objects in the environment so that they may be manipulated or acted upon. Individual differences in WM ability in healthy populations appear to reflect a core cognitive ability because they strongly predict an individual's fluid intelligenc as well as several aspects of scholastic achievement. Furthermore, WM deficits are a signature of many prevalent mental health disorders. Thus, a detailed understanding of this system is essential if we are to understand and treat psychopathologies that involve impaired cognition such as attention deficit/ hyperactivity disorder (ADHD) or schizophrenia. In addition, because of the tight link between online visual memory and basic processes for visual perception, our work will help to integrate basic knowledge about visual sensory processing (e.g., population coding of simple visual features) and online memory. One of the most fundamental attributes of WM is that it is greatly limited in capacity: capable of storing information about just a few objects at time, each with a limited level of precision. A key recent discovery is that these number and precision limits are distinct facets of WM capacity. However, the neural mechanisms that underlie these two factors that determine capacity are not currently understood. Here, we are developing neural oscillatory and hemodynamic measures that enable tracking of both between- and within-subject variations in these abilities. Specifically, our preliminary data show that the number of items held in WM is indexed on a trial-by-trial basis by desynchronization in alpha power (8-12hz) and WM precision is indexed by the dispersion of sensory population codes (quantified via novel multivariate analyses of fMRI and EEG data). The proposed research will employ psychophysics, fMRI, and EEG to measure the neural signals that track number and precision in WM. These efforts will provide new insights into the functional subdivisions of visual WM, and build clear bridges between well characterized behavioral measures of online memory ability and measures of oscillatory activity in humans. Finally, we will also examine the interactions between visual WM and visual long term memory (LTM) to determine how the contents of WM determine that which is encoded into LTM. These studies will help to characterize the role of visual WM in associative learning and clarify the roles of each system in the guidance of complex behaviors. By more precisely understanding how healthy individuals differ in WM ability and visual sensory function, we hope to develop methods and procedures that can be used to more accurately detect and characterize disease states in populations with mental health disorders, and to diagnose and quantify disorders in visually-guided behavior.