Information & Hierarchical Organization in the Neural Systems for Working Memory

我们的长期目标是了解使目前 以最佳方式影响认知和行为的相关信息。作为下一步 为了实现这一目标，这一拟议项目的目标是检验以下假设 工作记忆(WM)的神经系统是信息域依赖的， 按等级组织的。我们建议，物品，如对象、单词和位置， 表示在此层次结构的较低级别，而有关关系的信息 在这些对象中，具有潜在反应和奖励的对象被表示为 在前额叶皮质的更前部区域中，使用类似的 这两种信息的神经机制。我们将使用以下工具验证这一假设 健康年轻人的功能和解剖磁共振成像，以及 多发性硬化症患者。我们将测量内存负载的影响， 重复，并直接更新fMRI的激活幅度和模式 比较这些对项目和关系信息的影响。功能磁共振成像功能连接 项目的WM期间将与关系的WM期间的功能连接性进行对比 为了确定前额叶之间以及前额叶之间的相互作用 对于这些不同的信息类型，感觉区域是不同的。……的必要性 这些相互作用将通过使用DTI牵引术在患有多发性硬化的个体中进行测试。 硬化症测试WM的表现是否取决于物品的完整性不同 对于关系信息，白质比WM更容易理解。这项研究旨在测试 是否可以确定工作记忆维护与 项目，如对象、位置和单词，已被广泛研究，以及 “执行控制”功能，人们对此知之甚少。这个目标是非常高的 与该机构的使命有关，因为这些较高的认知功能 在许多精神障碍和神经疾病中被破坏。如果没有一个明确的 对使这些能力成为可能的神经系统的了解，我们几乎没有 提供认知功能障碍的治疗或预防。

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.