Multiscale Analysis of Neuronal Morphology

描述(申请人提供)：正常衰老和神经退行性疾病的认知障碍伴随着多个尺度上的形态变化：从单个脊椎的细粒几何形状到多个神经元和血管网络的全局拓扑，这些网络因占位性组织病理损害而扭曲。从机制上理解这些结构变化在产生观察到的认知缺陷中的作用需要准确的神经元形态的3D表示，以及现实的生物物理建模，这些生物物理模型可以直接将多个尺度上的结构变化与改变的神经元放电模式联系起来。然而，到目前为止，还没有能够在局部和全球尺度上以及真正的3D下解析、数字化和分析神经元形态的工具。该项目的中心目标是开发一个自动化分析系统，用于详细和准确的神经元形态的数字化、三维重建和几何分析，能够处理横跨局部脊柱几何形状的尺度上的形态细节，通过复杂的树状拓扑结构到多神经元网络的总体空间布置。作为一个具体的例子，我们将分析阿尔茨海默病(AD)Tg2576小鼠模型的形态变化，在该模型中，淀粉样沉积、皮质微血管改变和神经异常提供了易于识别的病理损害示例。有四个具体目标将针对这一广泛目标：(1)开发一个半自动的系统，用于从激光扫描显微镜(LSM)的图像数据中提取3D树和进行脊柱分析，具有亚体素分辨率，以便在最精细的尺度上进行准确的神经元形态测量；(2)对单个神经元、多神经细胞和血管网络以及来自人类和Tg2576 AD小鼠模型的衰老斑块进行成像和数字化；(3)开发3D空间复杂细胞结构全局分析工具；(4)分发和维护所有软件，并开发数据库驱动的网络存储库，用于数字化神经元和网络的分布。通过在多个尺度上提供复杂神经结构的真实3D形态测量，本研究中开发的工具将使未来的多尺度生物物理建模研究能够测试假想的机制，通过这些机制，正常衰老和神经退行性疾病中改变的树突结构、脊柱几何形状和网络分支模式决定工作记忆和认知功能的病理。这些研究将为记忆诱导和维持的一般机制提供重要的见解，这些机制是正常认知功能的基础，疾病状态下的记忆功能障碍，以及记忆恢复的潜在机制。

DESCRIPTION (provided by applicant): Cognitive impairment in normal aging and neurodegenerative disease is accompanied by altered morphologies on multiple scales: from the fine-grained geometry of individual spines to the global topologies of multi-neuron and vasculature networks that are distorted by space-occupying histopathologic lesions. A mechanistic understanding of the role of these structural changes in producing the observed cognitive deficits requires accurate 3D representations of neuronal morphology, and realistic biophysical modeling that can directly relate structural changes on multiple scales to altered neuronal firing patterns. To date however, no tools capable of resolving, digitizing and analyzing neuronal morphology on both local and global scales, and in true 3D, have been available. The central goal of this project is development of an automated analysis system for digitization, 3D reconstruction and geometric analysis of detailed and accurate neuronal morphology, capable of handling morphologic details on scales spanning local spine geometry through complex tree topology to the gross spatial arrangement of multi-neuron networks. As a specific example we will analyze morphologic changes in a Tg2576 mouse model of Alzheimer's disease (AD), in which amyloid deposition, altered cortical microvasculature and neural abnormalities provide easily identifiable examples of pathologic lesions. Four Specific Aims will address this broad objective: (1) To develop a semi-automated system for 3D tree extraction and spine analysis from laser scanning microscopy (LSM) imaged data, with sub-voxel resolution for accurate neuronal morphometry at the finest scales; (2) to image and digitize in 3D individual neurons, multineuron and vasculature networks, and senile plaques from human and Tg2576 mouse models of AD; (3) to develop tools for global analysis of spatially complex cellular structures in 3D; (4) to distribute and maintain all software, and develop a database-driven web repository for distribution of digitized neurons and networks. By providing true 3D morphometry of complex neural structures on multiple scales, the tools developed in this study will enable future multiscale biophysical modeling studies capable of testing hypothesized mechanisms by which altered dendritic structure, spine geometry and network branching patterns in normal aging and neurodegenerative disease determine pathologies of working memory and cognitive function. Such studies will provide crucial insight into general mechanisms of memory induction and maintenance that underlie normal cognitive function, its dysfunction in diseased states, and potential mechanisms for its restoration.