Imaging of Cognition, Learning and Memory in Aging

相对于年轻人，老年人在记忆的外显测试中表现出缺陷，例如识别测试以及工作记忆测试。此外，流行病学和神经影像学研究表明，对年龄相关的记忆变化的敏感性不同，这与教育，智商和参与休闲活动等变量有关。我们假设有两个互补的方面来储备年龄的影响：认知储备描述了正常的个体差异，在执行任务的能力。这种差异性的能力，可能会导致一些人不太容易受到 比其他人的影响。补偿是使用年轻人通常不使用的替代大脑网络来应对衰老的影响。这项研究旨在探索与年龄相关的记忆缺陷的神经机制以及针对这些变化的差异储备。我们有三个关键问题：1）年轻人任务表现变异的神经系统是什么？2)健康的老年人是使用同样的系统，还是使用替代的补偿系统？3)这些系统的使用如何与与储备相关的因素有关，如智商和教育。我们建议描绘这些神经系统与fMRI认知激活研究。具体目标是：1.在年轻和老年受试者中，识别大脑网络，其表达随两个任务的任务负荷而变化，延迟匹配样本任务（斯滕贝格任务，工作记忆）和连续非语言识别（识别记忆）。 2.探索网络变化，因为性能受到影响任务处理特定方面难度的操纵的挑战。3.比较这些负载敏感网络在年轻和老年受试者中的表达，以确定哪些神经网络的任务表现是相似的，以及哪些神经网络随着年龄的变化而变化。4.评估对任务负荷的反应如何随已知调节认知储备的变量（包括智商和教育）而变化，以确定与认知储备和补偿相关的神经网络。

Older adults demonstrate deficits, relative to young adults, in explicit tests of memory, such as recognition tests, as well as tests of working memory. In addition, epidemiologic and neuroimaging studies suggest that there is differential susceptibility to age-related memory changes that is related to variables such as education , IQ, and engagement in leisure activities. We have hypothesized that there are two complementary facets to reserve against the effects of aging: Cognitive reserve describes the normal individual differences in the capacity to perform tasks. This differential capacity, might result in some people being less susceptible to the effects of aging than others. Compensation is the use of alternate brain networks not normally used by younger individuals as a response to the effects of aging. The proposed research is aimed at exploring the neural mechanisms that underlies age-related memory deficits and the differential reserve against these changes. We have three key questions: 1) What are the neural systems that underlie variability in task performance in young adults? 2) Do healthy elders use these same systems, or do they use alternate compensatory systems? 3) How does of the use of these systems relate to factors that have been associated with reserve, such as IQ and education. We propose to delineate these neural system with five fMRI cognitive activation studies. The specific aims are to: 1. In young and elderly subjects, identify brain networks whose expression varies as a function of task load on two tasks, delayed match to sample task (Sternberg task, working memory), and continuous non-verbal recognition (recognition memory). 2. Explore network changes as performance is challenged by manipulations that affect the difficulty of specific aspects of task processing. 3. Compare expression of these load-sensitive networks in young and elderly subjects, to determine which neural networks underlying task performance are similar, and which change as a function of aging. 4. Evaluate how response to task load varies as a function of variables known to mediate cognitive reserve, including IQ and education, in order to identify neural networks associated with cognitive reserve and compensation.