Spatial Analysis of Cerebral Cortex in Aging Monkeys

描述（由申请人提供）：用于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滞后了。微柱是一种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，我们将采用源自统计物理学的方法来分析神经元被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 资助的项目的一部分，这些组织已经针对与年龄相关的认知衰退敏感的任务进行了行为测试。初步数据证实，前额叶皮层微柱强度与年龄有关。我们将测试以下假设：（1）尽管没有神经元死亡，但神经元微柱的空间组织在正常衰老过程中被破坏； (2)微柱的破坏与年龄相关的认知能力下降有关。因此，在目标 1 中，我们将开发一种全自动密度图方法来量化不同互连皮层区域的平均“微柱”结构，这些皮层区域是相关认知功能电路的一部分。为了有效地做到这一点，我们将把我们的方法应用于用硫堇染色的 30 微米厚冷冻切片的标准全脑冠状系列。由于此类部分在 z 平面上急剧收缩，因此它们仅提供二维 (2D) 的空间神经元位置。在目标 2 中，我们将把我们的分析扩展到 3D，通过从 z 维度上没有差异收缩的厚赛璐珞切片以及用共聚焦显微镜分析的免疫细胞化学染色切片获取 x、y、z 神经元位置来验证 2D 密度图方法。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目标 1 的 2D 密度图。在目标 3 中，我们将识别微柱组织中显示出与年龄相关的变化的区域，然后确定这些破坏是否与与年龄相关的认知能力下降有关。这些调查的重要性源于两个因素。首先，目前可用的方法只能部分检验所提出的假设，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且可靠的新方法。其次，将这些方法应用于正常衰老的神经解剖学可能使我们能够检测到皮质结构的微妙的、亚致死的变化，这些变化反映了当神经元损失不是一个因素时进行性神经元功能障碍。

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.