Information & Hierarchical Organization in the Neural Systems for Working Memory

描述（由申请人提供）：我们的长期目标是了解使当前相关信息能够最佳地影响认知和行为的神经机制。作为实现这一目标的下一步，本项目的目标是测试的假设，即工作记忆（WM）的神经系统是信息域依赖和层次组织。我们建议，项目，如对象，单词和位置，表示在这个层次结构的较低水平，而这些对象之间的关系，并与潜在的反应和奖励的信息表示在这个层次结构的更高水平的前额叶皮层更前部的区域使用类似的神经机制，这两种类型的信息。我们将在健康的年轻人和多发性硬化症患者中使用功能和解剖磁共振成像来验证这一假设。我们将测量记忆负荷、重复和更新对功能磁共振成像激活幅度和模式的影响，直接比较项目与关系信息的这些影响。功能磁共振成像功能连接在WM的项目将对比功能连接在WM的关系，以确定是否前额叶区之间的相互作用和前额叶区和感觉区之间的这些不同的信息类型是不同的。这些相互作用的必要性将通过在多发性硬化症患者中使用DTI纤维束成像来测试，以测试WM对项目的表现是否取决于不同白色物质束的完整性，而不是WM对关系信息的完整性。这项研究旨在测试是否可以确定的概念之间的联系，工作记忆维护的项目，如对象，位置和单词，这已被广泛研究，和“执行控制”的功能，这是不太好理解。这一目标与该机构的使命高度相关，因为这些高级认知功能在许多精神障碍和神经系统疾病中受到干扰。如果没有对使这些能力成为可能的神经系统的清晰理解，我们就无法为治疗或预防认知功能障碍提供帮助。公共卫生相关性：这项研究将增强我们对大脑机制和系统的理解，使我们能够记住当前相关的信息，以便它可以帮助指导目标导向的行为。这种理解将有助于指导未来的研究，以开发这些能力受损的治疗方法。

DESCRIPTION (provided by applicant): Our long-term objective is to understand the neural mechanisms that enable currently relevant information to optimally influence cognition and behavior. As the next step in achieving this objective, the goal of this proposed project is to test the hypothesis that the neural system for working memory (WM) is information-domain-dependent and hierarchically organized. We propose that items, such as objects, words, and locations, are represented at the lower levels of this hierarchy while information about relationships among these objects and with potential responses and rewards is represented at higher levels of this hierarchy in more anterior regions of the prefrontal cortex using similar neural mechanisms for both types of information. We will test this hypothesis using functional and anatomical magnetic resonance imaging in healthy young adults, and individuals with multiple sclerosis. We will measure the effects of memory load, repetition, and updating on the fMRI activation magnitude and pattern, directly comparing these effects for item vs. relational information. fMRI functional connectivity during WM for items will be contrasted to functional connectivity during WM for relations to ascertain whether interactions among prefrontal areas and between prefrontal areas and sensory areas are different for these different information types. The necessity of these interactions will be tested by using DTI tractography in individuals with multiple sclerosis to test whether WM performance for items depends on the integrity of different white matter tracts than does WM for relational information. The study aims to test whether a conceptual link can be identified between working memory maintenance of items, such as objects, locations, and words, which has been extensively studied, and "executive control" functions, which are much less well understood. This goal is highly relevant to the mission of the agency because these higher cognitive functions are disrupted in many mental disorders and neurological diseases. Without a clear understanding of the neural systems that make these abilities possible, we have little to offer for treatment or prevention of cognitive dysfunction. PUBLIC HEALTH RELEVANCE: This study will enhance our understanding of the brain mechanisms and systems that enable us to remember currently relevant information so that it can help guide goal- directed behavior. This understanding will help guide future research to develop treatments for impairments in these abilities.