Investigations of the dynamic nature of intrinsic brain networks

描述（由申请人提供）：大脑具有惊人的能力，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、基线环境的力量是短暂的，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，例如由于衰老，脑损伤或精神疾病而发生的变化。最近有一个重点是测量的内在功能连接的网络的大脑区域在休息时使用功能磁共振成像（fMRI）。将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基本独立的网络的程度（或模块），以及识别单个大脑区域的作用，例如一个区域是否是跨多个大脑区域和网络的通信的组成部分，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。这项提议旨在将这种内在大脑网络的特征扩展到其他环境，以评估大脑在不同环境中的可塑性潜力。因此，拟议的研究将在两种不同的背景下调查全球大脑组织的重新配置和个体大脑区域从内在网络配置中的角色变化：1）功能中断， 局灶性脑损伤，以及2）由于认知任务的不同条件的施用而引起的特定认知需求。方法：本研究提案将采用最先进的方法和分析来解决具体目标。第一个实验将分析从局灶性脑损伤患者和年龄匹配的健康对照组收集的数据，以评估脑损伤后网络重构的程度。我假设，如果完整组织在维持脑损伤的网络中的作用改变为与受损组织在健康的内在脑组织中的作用更相似，那么自适应网络重构就会发生。我预测，网络内适应是一种更准确的方式来表征大脑组织中的补偿性变化，而不是纯粹关注解剖学上接近受损组织的完整组织（即，病灶周围组织）或在未损伤的同源区域中的完整组织上（即，对侧）半球。第二个实验将检查健康年轻人大脑在不同认知环境中的重构能力。我假设自适应网络重新配置将通过将网络组织改变为单个特定于上下文的网络来实现，该网络由认知相关区域和跨独立内在网络的连接组成。至关重要的是，这种重新配置的自适应性将通过相关的行为表现的程度，该区域的任务性能是重要的上下文特定的网络内的通信进行评估。

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.