Neuroanatomic Change and Attention Dynamics in Aging

这项研究的总体目标是检查健康老龄化中大脑结构变化与注意力缺陷的关系。 注意力资源分配和再分配的速度会影响感觉处理和行为反应的速度，而这两者都随着年龄的增长而减慢。 事实上，许多被认为对空间注意功能很重要的大脑区域，包括前额叶和顶叶皮层、丘脑，以及最近的小脑，都被报道显示出与年龄相关的变化。 我们建议使用结构和功能成像方法，以检查是否结构变化和随后的功能低下，在这些皮质和皮质下区域，特别是小脑，可能会导致注意力不足的老化。 具体来说，我们建议1）确定大脑结构的变化发生与健康老龄化的横断面样本，2）以确定行为和脑电图的变化，在老龄化与转移或定向的注意力，和3）测试的假设，年龄相关的损失后小脑可能会影响前注意力定向系统，和后空间注意力映射系统。 这些大脑网络的效率降低会导致注意力转移和定向的减缓，以及大脑电生理动力学的相关变化。我们将研究120名年龄在21-85岁之间的男性和女性。 所有受试者将接受：（1）神经心理学评估;（2）MR成像，对感兴趣的皮质和皮质下区域的灰质和白色物质以及CSF进行定量，以及颅内空间的高信号;（3）注意力转移任务，旨在分离与感觉、运动和注意力过程相关的电生理和血液动力学活动。 行为，事件相关电位（ERP），功能磁共振成像（fMRI）的数据记录在这些任务将与神经解剖学的结果进行比较，以解决我们的研究假设。 基于独立成分分析的新分析技术将使我们能够识别整个大脑的相关fMRI信号变化，以及来自ERP数据的相干EEG的重叠模式。 拟议的实验将产生收敛的证据有关的神经基础的动态注意力不足的老化。 这些数据还将提供方法以及神经解剖测量的基线数据集，可用于未来的临床研究。

The overall goal of this research is to examine the association of brain structural changes with attentional deficits in healthy aging. The speed with which attentional resources can be allocated and re-allocated affects the speed of sensory processing and behavioral responding, both of which are slowed with aging. A number of the brain regions that have been identified as important to spatial attentional function, including prefrontal and parietal cortex, the thalamus, and most recently the cerebellum, have, in fact, been reported to show age-related change. We propose to use structural and functional imaging methods to examine whether structural changes and subsequent functional inefficiency in these cortical and subcortical regions, particularly the cerebellum, may underlie attention deficits in aging. Specifically, we propose 1) to identify brain structural changes occurring with healthy aging in cross-sectional samples, 2) to identify behavioral and EEG changes in aging associated with shifting or orienting of attention, and 3) to test the hypothesis that age-related loss in the posterior cerebellum may affect both an anterior attention orienting system, and a posterior spatial attention mapping system. Reduced efficiency in these brain networks would result in slowed attentional shifting and orienting, and associated changes in brain electrophysiological dynamics. We will study 120 males and females aged 21-85. All subjects will receive: (1) neuropsychological evaluation; (2) MR imaging with quantification of gray and white matter and CSF in cortical and subcortical regions of interest, and hyperintensities in intracranial space; (3) attention shift tasks designed to allow separation of electrophysiological and hemodynamic activities linked to sensory, motor, and attentional processes. Behavioral, event-related potential (ERP), and functional magnetic imaging (fMRI) data recorded during these tasks will be compared with neuroanatomic results to address our research hypotheses. New analytic techniques based on Independent Component Analysis will allow us to identify both correlated fMRI signal changes throughout the brain, and overlapping patterns of coherent EEG from ERP data. The proposed experiments will yield convergent evidence concerning the neurologic bases of dynamic attention deficits in aging. These data will also provide methods as well as a baseline dataset of neuroanatomic measures that could be used in future clinical studies.