Investigations of the dynamic nature of intrinsic brain networks

描述（由申请人提供）：大脑有一种惊人的能力，可以根据不断变化的环境的需求灵活地参与不同的功能网络。有时，作用于内在的基线环境的力是短暂的，例如日常生活的动态认知需求。在其他时候，它们是长期的，偶尔是永久性的，比如由于衰老、脑损伤或精神疾病而发生的变化。近年来，利用功能磁共振成像（fMRI）测量休息时大脑区域网络的内在功能连通性已成为研究热点。将来自数学领域的图论工具应用于这些内在的大脑网络，可以量化网络属性，例如大脑区域组将自己分离成很大程度上独立的网络（或模块）的程度，以及识别单个大脑区域的作用，例如一个区域是否为跨多个大脑区域和网络的通信不可或缺。或者一个区域是否将其相互作用限制在单个网络内的一小部分大脑区域。本研究旨在将大脑内在网络的特征扩展到其他环境，以评估大脑在不同环境下的可塑性潜力。因此，本研究将在两种不同的背景下，从内在的网络配置出发，研究全球大脑组织的重构和单个大脑区域的角色变化：1)功能中断

DESCRIPTION (provided by applicant): The brain has an amazing ability to flexibly engage different functional networks based on the demands of a constantly changing environment. Sometimes forces acting on an intrinsic, baseline environment are transient, such as the dynamic cognitive demands of daily life. At other times they are longer term, and occasionally permanent, such as the changes that occur due to aging, brain damage, or psychiatric disorders. Recently there has been a focus on measuring the intrinsic functional connectivity of networks of brain regions during rest using functional MRI (fMRI). The application of graph theoretical tools taken from the field of mathematics to these intrinsic brain networks allows for the quantification of network properties, such as the degree to which groups of brain regions separate themselves into largely independent networks (or modules), and the identification of the role of individual brain regions, such as whether a region is integral for communication across multiple brain regions and networks, or whether a region limits its interactions to a small subset of brain regions within a single network. This proposal aims to extend this characterization of intrinsic brain networks to other contexts to assess the brain's potential for plasticity in different contexts. The proposed research, therefore, will investigate both the reconfiguration of global brain organization and the changing roles of individual brain regions from intrinsic network configuration in two different contexts: 1) disruption of functioning due to focal brain lesions, and 2) specific cognitive demands due to administration of different conditions of a cognitive task. METHOD: This research proposal will apply state-of-the-art methodologies and analyses to address the specific aims. The first experiment will analyze data that was collected from patients with focal brain lesions and age-matched healthy controls to assess the extent of network reconfiguration after brain damage. I hypothesize that adaptive network reconfiguration will occur if the role of intact tissue within the network that sustained te brain damage changes to be more similar to the role that the damaged tissue had in healthy, intrinsic brain organization. I predict that within-network adaptation is a more accurate manner of characterizing compensatory changes in brain organization than is focusing purely on intact tissue anatomically close to the damaged tissue (i.e., perilesional tissue) or on intact tissue in homologous regions in the undamaged (i.e., contralesional) hemisphere. The second experiment will examine the brain's ability to reconfigure in different cognitive contexts in healty young adults. I hypothesize that adaptive network reconfiguration will occur by changing network organization toward a single context-specific network made up of cognitively relevant regions and connections across separate intrinsic networks. Critically, the adaptive nature of this reconfiguration will be assessed by relating behavioral performance to the degree to which regions integral for task performance are important for communication within that context-specific network.