Plasticity of the white matter after brain stroke

描述(由申请人提供) 脑中风是世界上最常见的医学和社会问题之一，也是导致慢性残疾的主要原因。在急性期幸存下来的患者可能会部分恢复失去的大脑功能。这种功能恢复过程的一部分归因于大脑的可塑性。我们认为皮质和白质的组织结构在决定可塑性方面起着重要作用。识别和了解这一过程中涉及的因素不仅可能有助于了解大脑功能，还可能有助于设计新的急性中风治疗方案。为了与美国国立卫生研究院研究预防和减轻神经系统疾病负担的方法相一致，我们建议分析中风后皮质和白质结构变化的演变。虽然功能成像对皮质可塑性的研究相对较好，但到目前为止，白质重组仍是一个棘手的问题。新的分析工具的发展，如扩散张量磁共振成像(DT-MRI)，使这一重要问题能够得到适当的评估。因此，本研究计划的总体目标是建立卒中后影响运动功能的患者连通束的变化。我们将：1)建立卒中后亚急性期和慢性期脑白质DT-MRI图谱。该方法使用分数各向异性(FA)和表观系数扩散(ADC)测量来间接确定神经纤维的构筑；2)用功能磁共振(FMRI)在卒中后亚急性和慢性期建立运动任务时的激活区域，以研究皮质重写及白质重塑；3)比较卒中后亚急性和慢性期患侧大脑与非受累半球及正常对照组大脑的DT-MRI，以探讨白质可能的重塑及其发生在哪个阶段。我们将使用基于像素的分析和基于手动感兴趣区域(R01)的分析和更全局的归一化方法来检测未被先验怀疑的区域的差异；4)检测同一个体中风后不同阶段DT-MRI和fMRI的差异并将其与患者预后指数评分模型进行比较，试图建立与功能恢复相关的连接模式；5)分析患者DT-MRI和fMRI之间的关系，以将皮质激活的变化与新的白质连接的发展或现有路径的招募相关联。6)使用轨迹照相术在感兴趣的区域之间建立连接。如果在AIMS#1至#5中进行的分析可能会识别具有功能演变迹象的白质重塑区域。我们将使用这些区域的末端作为种子点来设计兴趣点。

DESCRIPTION (supplied by applicant) Brain stroke is one of the most common medical and social problems in the world and a leading cause of chronic disabilities. Patients who survive the acute phase may partially recover some of the lost brain functions. Part of this process of functional recovery is attributed to brain plasticity. We believe that tissue organization in cortex and white matter plays an important role in determining plasticity. Identifying and understanding the factors involved in this process will likely contribute not only to the understanding of brain function but also to the design of novel therapeutic options for acute stroke. In agreement with the NIH mission of investigating ways to prevent and reduce the burden of neurological diseases, we propose to analyze the evolution of cortical and white matter architectural changes after stroke. Though cortical plasticity is relatively well explored by functional imaging, white matter reorganization was up to now an intractable problem. The development of new analytical tools, such as the diffusion tensor- magnetic resonance imaging (DT-MRI), allows this important issue to be properly assessed. Therefore, the general goal of this research program is to establish the changes of connectivity tracts in patients after stroke affecting motor function. We will: 1) Establish the DT-MRI maps of white matter in subacute and chronic phases post-stroke. This method uses fractional anisotropy (FA) and apparent coefficient diffusion (ADC) measurements to indirectly determine the architecture of neuronal fibers; 2) Establish the active areas during a motor-task with functional MRI (fMRI) in subacute and chronic phases post-stroke to study cortical rewriting in addition to white matter remodeling; 3) Compare DT-MRI in the affected hemispheres in the subacute and chronic phases post-stroke with non-affected hemispheres and with normal control' brains to investigate a possible remodeling of white matter and in which phase post stroke it occurs. We will use a pixel-based analysis with manual-regions of interest (R0l)-based and a more global normalization-based approach to detect differences in areas not suspected a priori; 4) Detect differences on DT-MRI and fMRI between phases post stroke in the same individual and compare them with a score model of patient outcome indices, trying to establish a pattern of connectivity related to recovering of function; 5) Analyze the relationship between DT-MRI and fMRI of patients to correlate alterations in cortical activation with development of new white matter connections or recruitment of pathways that already exist. 6) Establish the connectivity among the areas of interest using tractography. If the analyses performed in aims #1 through #5 will likely identify areas of white matter remodeling with signs of functional evolvement. We will use the end of these areas to use as seed points to design the points of interest.