Spatial Analysis of Cerebral Cortex in Aging Monkeys

描述（由申请人提供）：分析神经元数量的定量方法推动了我们对大脑知识的进步，但研究空间组织的方法却落后了。微柱是一个独特的垂直空间组织，是大脑皮层的特征。为了定量评估微柱结构，我们将采用统计物理学的方法来分析神经元组织成微柱时的局部空间关系。这些研究的组织将免费从年轻、中年和老年恒河猴身上获得，作为NIA资助项目的一部分，这些猴子已经在与年龄相关的认知衰退敏感的任务中进行了行为测试。初步数据证实，前额皮质微柱的强度与年龄有关。我们将检验以下假设：(1)在正常衰老过程中，尽管神经元没有死亡，但神经元微柱的空间组织被破坏；(2)微柱破坏与年龄相关的认知能力下降有关。因此，在Aim 1中，我们将开发一种全自动密度图方法来量化不同相互连接的皮层区域的平均“微柱”结构，这些区域是相关认知功能回路的一部分。为了有效地做到这一点，我们将把我们的方法应用于标准的全脑冠状系列，30微米厚的冷冻切片，用硫蛋白染色。由于这些切片在z平面上急剧缩小，因此它们只能提供二维（2D）的空间神经元位置。在Aim 2中，我们将把我们的分析扩展到3D，通过从厚的纤维蛋白切片中获取x，y，z神经元位置来验证二维密度图方法，这些纤维蛋白切片在z维度上没有差异收缩，以及用共聚焦显微镜分析的免疫细胞化学染色切片。然后，我们将扩展我们的方法来生成3D密度图，并确定“校正”因子是否可以应用于Aim 1的2D密度图。在Aim 3中，我们将确定微柱组织中显示年龄相关变化的区域，然后确定这些破坏是否与年龄相关的认知能力下降有关。这些调查的重要性来自两个因素。首先，目前可用的方法只能部分地测试所提出的假设，因此我们开发和验证的方法将为量化局部空间关系提供有效和可靠的新方法。其次，将这些方法应用到正常衰老的神经解剖学中，可能使我们能够发现细微的、亚致死的皮层结构变化，这些变化反映了在神经元丧失不是一个因素的情况下神经元功能障碍的进展。

DESCRIPTION (provided by applicant): Quantitative methods for analyzing neuronal numbers have fueled advances in our knowledge of the brain but methods to study spatial organization have lagged. The microcolumn is a distinct vertical spatial organization that characterizes cerebral cortex. To quantitatively assess microcolumnar structure, we will adapt methods derived from statistical physics to analyze local spatial relationships among neurons as they are organized into microcolumns. Tissue for these studies will be obtained at no cost from young, middle aged and elderly rhesus monkeys that, as part of an NIA funded Program Project, have been behaviorally tested on tasks sensitive to age-related cognitive decline. Preliminary data confirms an age-related reduction in the strength of microcolumns in the prefrontal cortex. We will test the following hypotheses: (1) spatial organization of neurons into microcolumns is disrupted in normal aging despite of the lack of neuronal death; and (2) disruption of microcolumns will be associated with age-related cognitive decline. Hence, in Aim 1 we will develop a fully automated density map method to quantify the average "microcolumnar" structure across diverse interconnected cortical regions which are part of the circuitry of the pertinent cognitive functions. To do this efficiently we will apply our method to standard whole brain coronal series of 30 micron thick frozen sections stained with thionin. Because such sections shrink dramatically in the z plane, they only provide spatial neuronal locations in two dimensions (2D). In Aim 2 we will extend our analysis to 3D to validate the 2D density map method by acquiring x,y,z neuronal locations from thick celloidin sections that don't differentially shrink in the z dimension, as well as immunocytochemically stained sections analyzed with the confocal microscope. We will then extend our method to generate 3D density maps and determine if "correction" factors can be applied to the 2D density maps of Aim 1. In Aim 3 we will identify regions showing age-related changes in microcolumnar organization and then determine if these disruptions are associated with age-related cognitive decline. The importance of these investigations derives from two factors. First, currently available methods can only partially test the hypotheses proposed, so the methods we develop and validate will provide efficient and reliable new ways to quantify local spatial relationships. Second, the application of these methods to neuroanatomy of normal aging may allow us to detect subtle, sublethal, changes in cortical structure that reflect progressive neuronal dysfunction when neuronal loss is not a factor.