Imaging of Cognition, Learning and Memory in Aging

与年轻人相比，老年人在识别测试和工作记忆测试等外显记忆测试中表现出缺陷。此外，流行病学和神经成像研究表明，与年龄相关的记忆变化的易感性存在差异，这些变化与教育、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应对衰老的影响：认知储备描述了正常的个体执行任务能力的差异。这种不同的能力，可能会导致一些人不太容易受到 衰老的影响比其他因素更大。补偿是指使用年轻人通常不会使用的备用大脑网络来应对衰老的影响。这项拟议的研究旨在探索与年龄相关的记忆缺陷和针对这些变化的差异储备背后的神经机制。我们有三个关键问题：1)导致年轻人任务表现差异的神经系统是什么？2)健康的老年人是使用相同的系统，还是使用替代的补偿系统？3)这些系统的使用与智商和教育等与储备相关的因素有什么关系。我们建议用五项fMRI认知激活研究来描绘这些神经系统。具体目的是：1.在年轻人和老年人中，识别其表达随任务负荷的变化而变化的大脑网络，这两个任务分别是延迟匹配到样本任务(Sternberg任务，工作记忆)和连续非语言识别(再认记忆)。 2.探索网络变化，因为性能受到影响任务处理特定方面的难度的操作的挑战。3.比较这些负荷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在任务绩效中相似，哪些随着年龄的变化而变化。4.评估对任务负荷的反应作为已知的调节认知储备的变量的函数，包括智商和教育，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.