Dynamics in resting and task-based functional connectivity

描述(由申请人提供)：为了了解人脑是如何被组织起来处理和转换信息的，人们越来越认识到，需要对其构成的处理元素进行网络级别的描述。为此，基于结构和扩散的磁共振成像已经开始解释人类大脑的哪些部分在物理上相互连接，而静息状态功能连接磁共振成像(rs-fcMRI)已经揭示了该结构中大规模的长期大胆的相关关系。后一种描述通常假设这些关系在很长一段时间内是稳定的，但我们对大脑作为一个复杂的动态系统的理解表明，大脑网络的成员时不时地在不同的处理需求的背景下改变他们彼此的交互。这项提议旨在利用功能磁共振提供的独特的空间和时间分辨率组合来严格展示休息和任务期间大脑网络的动态特性。该提案有两个目的。第一个目标是描述在不受约束的REST设置中连接关系的动态波动。我们计划严格确定是否存在高度可变的关系以及在哪里存在高度可变的关系，这些动态如何与已知的模块化网络结构相关，以及已知功能社区之间是否存在动态模式。我们有初步证据表明存在有意义的动力学，但希望全面描述这些动力学的空间组织和时间特性，以深入了解它们如何与健康的大脑功能相关，并为识别疾病中的动态变化提供参考。第二个目的是通过在一个控制良好的任务环境中操纵它们来阐明相互关联中动力学的潜在生物学意义。具体地说，我们希望测试变化的外部任务需求是否会导致大脑中被认为涉及协调有效任务处理的区域的网络协调的瞬时变化。这将提供强有力的证据，证明除了局部的大胆活动外，分布式网络协调在处理信息方面的可观察作用，并将为解释病理性大脑中的处理失败提供一个替代框架。在资助人类连接组项目时，NIMH认识到准确和详细地描述健康人脑的结构和功能连接的重要性，这是理解精神健康障碍的关键一步。描述和分析这种连通性中的动态是这一任务的自然延伸，并将提供一个更敏感的空间，在其中了解大脑功能、功能障碍以及在发育和衰老过程中的变化。

DESCRIPTION (provided by applicant): In order to understand how the human brain is organized to process and transform information it has become increasingly recognized that a network-level description of its constituent processing elements is needed. To this end, structural and diffusion-based MRI have begun to explain which parts of the human brain are physically connected to each other, and resting state functional connectivity MRI (rs-fcMRI) has revealed large-scale long-term BOLD correlation relationships within that structure. This latter description has typically assumed stability in these relationships over long periods of time, but our understanding of the brain as a complex dynamic system suggests that members of the brain network change their interactions with each other moment-to-moment and in the context of different processing demands. This proposal aims to harness the unique combination of spatial and temporal resolution provided by functional MRI to rigorously demonstrate the dynamic properties of the brain network both at rest and during tasks. The proposal has two aims. The first aim is to characterize dynamic fluctuations in connectivity relationships in the unconstraine setting of rest. We plan to rigorously determine whether and where highly variable relationships exist, how these dynamics relate to the known modular network structure, and whether patterns of dynamics exist between known functional communities. We have preliminary evidence that meaningful dynamics exist, but wish to comprehensively describe the spatial organization and temporal properties of these dynamics, to give insight into how they relate to healthy brain function and to provide a reference for identifying altered dynamics in disease. The second aim is designed to illuminate the potential biological significance of dynamics in correlation by manipulating them in a well-controlled task setting. Specifically, we wish to test if changing external task demands induces transient changes in network coordination in regions of the brain believed to be involved in orchestrating effective task processing. This would provide strong evidence for an observable role of distributed network coordination in processing information in addition to localized BOLD activity, and would suggest an alternative framework for interpreting processing failures in pathological brains. In funding the Human Connectome Project, the NIMH recognized the importance of an accurate and detailed description of structural and functional connectivity in the healthy human brain as a critical step in understanding disorders of mental health. Description and analysis of dynamics in this connectivity is a natural extension of this mandate and will provide a more sensitive space in which to understand brain function, dysfunction, and changes over development and aging.