Relationship Between Neural Correlates of Episodic Memory,Age, Memory Performanc

描述（由申请人提供）：与大多数其他形式的记忆相比，情景记忆随着年龄的增长而显著下降，而情景记忆的严重损害是几种与年龄相关的神经退行性疾病的突出特征。了解健康受试者与年龄相关的偶发性衰退的认知和神经基础是很重要的，因为即使是进入70岁的健康个体典型的相对适度的损伤也足以对认知功能产生有害影响。因此，改善与年龄相关的记忆衰退的干预措施的发展将具有相当大的价值，并且将通过增加对其原因的了解而大大促进。同样重要的是，如果不了解记忆及其神经基质在健康衰老过程中是如何变化的，就很难全面了解阿尔茨海默病等病理条件下更严重的记忆障碍特征。本研究项目的主要目的是阐明支持情景记忆的认知过程中与年龄相关的神经相关差异的功能意义，确定这些差异中哪些反映了导致与年龄相关的记忆功能衰退的过程，哪些反映了改善这种衰退的补偿机制。该计划的重点是情景编码和检索的神经关联，通过fMRI的“后续记忆”和“检索成功”效应进行索引。该项目的出发点是，与20多岁的人相比，60多岁和70多岁的人在随后的记忆和检索成功效应的大小和皮层分布上表现出特征差异。其中一个差异表现为“右前额叶过度招募”——相对于年轻人，老年人的右前额叶皮层的后续记忆效应更大。最近的研究结果表明，右额叶过度吸收后续记忆效应与相对较差的记忆表现水平有关。五个实验将一起进行，将严格地描述情景编码和检索的神经关联与年龄、记忆表现和各种脑结构测量（包括白质完整性）之间的关系。这些研究包括对年轻人、中年人和老年人的编码和检索相关神经活动的大规模调查，一项纵向研究允许调查编码和检索效果与年龄相关的记忆衰退之间的关系，一项研究调查老年人随后的记忆效果如何随着学习任务的难度而变化。一项实验旨在验证这样一种假设，即在成功的情景检索过程中，老年人所引发的神经活动所携带的分化良好的信息少于年轻人。

DESCRIPTION (provided by applicant): Episodic memory declines substantially and, relative to most other forms of memory, disproportionately, with age, while a considerably more severe impairment of episodic memory is a prominent feature of several age-related neurodegenerative disorders. An understanding of the cognitive and neural bases of age-related episodic decline in healthy subjects is important because even the relatively modest impairment typical of healthy individuals entering their 70's is sufficient to have a detrimental impact on cognitive function. Thus, the development of interventions that ameliorate age-related memory decline would be of considerable value and would be much facilitated by increased understanding of its causes. Equally important, a full understanding of the more severe memory impairments characteristic of pathological conditions such as Alzheimer's Disease will be difficult to achieve without knowledge of how memory and its neural substrates change in the course of healthy aging. The overarching aim of the present research program is to elucidate the functional significance of age- related differences in the neural correlates of cognitive processes supporting episodic memory, determining which of these differences reflect processes that contribute to age-related decline in memory function, and which reflect compensatory mechanisms that ameliorate such decline. The focus of the program is on the neural correlates of episodic encoding and retrieval as indexed by fMRI 'subsequent memory' and 'retrieval success' effects. The program takes as its starting point findings indicating that, relative to individuals in their 20's, people in the 60's and 70's demonstrate characteristic differences in the magnitude and cortical distribution of subsequent memory and retrieval success effects. One of these differences takes the form of 'right frontal over-recruitment' - larger subsequent memory effects in the right prefrontal cortex in older relative to younger individuals. Recent findings indicate that right frontal over-recruitment of subsequent memory effects is associated with relatively poor levels of memory performance. Five experiments will be conducted that, together, will rigorously characterize the relationship between neural correlates of episodic encoding and retrieval and age, memory performance, and a variety of structural brain measures including white matter integrity. The studies include a large-scale investigation of encoding- and retrieval-related neural activity in young, middle-aged and older individuals, a longitudinal study permitting investigation of the relationship between encoding and retrieval effects and age-related memory decline, a study to investigate how subsequent memory effects vary with the difficulty of the study task in older people, and an experiment aimed at testing the hypothesis that the neural activity elicited during successful episodic retrieval carries less well- differentiated information in older than in young individuals.