DIFFUSION SPECTRUM MRI OF STRUCTURAL CHANGES IN WHITE MATTER IN DEMENTIA

痴呆症中白质结构变化的扩散谱 MRI

• 批准号: 8170581
• 负责人: VAN J WEDEEN
• 金额: $ 7.66万
• 依托单位: NORTHERN CALIFORNIA INSTITUTE/RES/EDU
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8170581
• 关键词: Adopted; Bilateral; Brain; Brain Stem; Cerebrum; Computer Retrieval of Information on Scientific Projects Database; Dementia; Development; Diffusion; Dimensions; Evolution; Fiber; Funding; Goals; Grant; Image; Institution; Location; Logic; Magnetic Resonance Imaging; Measures; Methods; Pathway interactions; Pattern; Physical condensation; Population; Primates; Property; Reporting; Research; Research Personnel; Resources; Scheme; Source; Spinal Cord; Structure; Surface; System; Textiles; To specify; United States National Institutes of Health; Variant; Vertebrates; meetings; white matter

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of this project has been to develop robust methods for analysis of brain connectivity using diffusion spectrum imaging. We have made progress in adopting an approach that enables discovery of correlated structures with the least possible bias. The approach we devised is to analyze for any fiber pathway the set of all other pathways that meet it, i.e by sharing a voxel in common. This represents a simple definition of path-adjacency, equivalent to specifying a topology on the space of paths, and so is among the most basic of geometric properties. Path-adjacency includes familiar end-to-end connectivity as a special case, but also measures other aspects of path proximity in 3-dimensions, including path tangency and path crossing, and so it represents a highly unbiased probe of the 3D relational structure of the fiber pathways. We report the results of a new way of analyzing the fiber connectivity revealed by applying these methods to diffusion spectrum imaging (DSI) MRI in multiple primate species. Whereas previous tractography has suggested that fiber crossing is sporadic, adjacency reveals crossing to be to be pervasive and highly organized. We have discovered a mesh or grid of near right-angled fiber crossings as a basic unit of path organization. At each location, cerebral white matter is resolved into biaxial systems of intersecting fiber pathways, resembling the warp and weft of fabric. We term this an ortholinear structure. Thus, bi-axial structure at different depths is parallel - extrinsically parallel, inasmuch as the planes are locally parallel as 2D surfaces in 3D, and also intrinsically parallel, as each of the two fiber populations within each sheet is parallel to its counterpart in the other sheet. In many locations, a third set of pathways perpendicular to the other two is also observed. It appears the mesh network is continuous throughout the entire brain and not simply in discrete locations. These results reveal a new and simplified view of the pattern of connections that we have described as an ortholinear organization. It is an extension of the simple pattern of longitudinal, bilateral and dorso-ventral connectivity that characterizes the spinal cord and brainstem of all vertebrates. Further, known fiber pathways are all recognized within this ortholinear scheme, and adhere to it, but now are seen less as distinct structures than as local condensations of pathways of a particular orientation. This newly revealed organization represents an absolute, natural coordinate system of the brain. This natural coordinate system, like its instantiations in the more caudal segments of the CNS, likely expresses the logic and means of brain evolution and development, and will provide a natural framework description of brain structure and variation.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 该项目的总体目标是开发使用扩散光谱成像分析大脑连接的强大方法。我们在采用一种方法方面取得了进展，这种方法能够以最小的偏差发现相关结构。我们设计的方法是分析任何纤维通路的所有其他通路的集合，即通过共享共同的体素。这代表了路径邻接的一个简单定义，等价于在路径空间上指定一个拓扑，因此是最基本的几何性质之一。路径邻接包括作为特殊情况的常见的端到端连接性，但也测量3维中路径邻近的其他方面，包括路径相切和路径交叉，因此它代表了光纤路径的3D关系结构的高度无偏探测。我们报告了一种分析纤维连接性的新方法的结果，该方法通过将这些方法应用于多个灵长类动物物种的扩散谱成像（DSI）MRI来揭示。而以前的纤维束成像表明，纤维交叉是零星的，相邻显示交叉是普遍的和高度有组织的。我们已经发现了一个网格或网格的近直角纤维交叉作为一个基本单位的路径组织。在每个位置，大脑白色物质被分解成交叉纤维通路的双轴系统，类似于织物的经线和纬线。我们称之为正交线性结构。因此，在不同深度处的双轴结构是平行的-外平行的，因为平面在3D中作为2D表面是局部平行的，并且也是内在平行的，因为每个片材内的两个纤维群中的每一个平行于另一片材中的其对应物。 在许多地方，还可以观察到与其他两个通道垂直的第三组通道。网状网络似乎在整个大脑中是连续的，而不仅仅是在离散的位置。这些结果揭示了一个新的和简化的视图，我们已经描述为一个正交线性组织的连接模式。它是所有脊椎动物的脊髓和脑干的纵向、双侧和背腹连接的简单模式的延伸。 此外，已知的纤维路径都在这个正交线性方案中被识别，并坚持它，但现在被视为一个特定方向的路径的局部凝聚，而不是作为不同的结构。 这个新发现的组织代表了大脑的一个绝对的、自然的坐标系统。这个自然的坐标系统，就像它在中枢神经系统尾部的实例一样，可能表达了大脑进化和发展的逻辑和手段，并将提供大脑结构和变化的自然框架描述。