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

描述（由申请人提供）：情节记忆随着年龄的增长而显著下降，并且相对于大多数其他形式的记忆，不成比例地下降，而情节记忆的相当严重的损害是几种与年龄相关的神经退行性疾病的突出特征。了解健康受试者中与年龄相关的偶发性衰退的认知和神经基础是重要的，因为即使是进入70多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不利影响。因此，开发改善与年龄相关的记忆衰退的干预措施将具有相当大的价值，并将通过增加对其原因的了解而得到极大的促进。同样重要的是，如果不了解记忆及其神经基质在健康老龄化过程中如何变化，就很难充分了解阿尔茨海默病等病理条件下更严重的记忆障碍特征。 本研究计划的总体目标是阐明支持情景记忆的认知过程的神经相关物中与年龄相关的差异的功能意义，确定这些差异中的哪些反映了有助于与年龄相关的记忆功能下降的过程，哪些反映了改善这种下降的补偿机制。该计划的重点是对神经相关的情节编码和检索的功能磁共振成像“后续记忆”和“检索成功”的影响。该计划的出发点是，研究结果表明，相对于20多岁的人，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方面表现出特征性差异。其中一个差异表现为“右额叶过度募集”，即相对于年轻人，老年人右前额皮质的后续记忆效应更大。最近的研究结果表明，右额叶过度招募随后的记忆效应与相对较差的记忆表现水平。将进行五个实验，一起，将严格表征神经相关的情节编码和检索和年龄，记忆性能，和各种结构的大脑措施，包括白色物质的完整性之间的关系。这些研究包括对年轻人、中年人和老年人编码和提取相关神经活动的大规模调查，允许调查编码和提取效应与年龄相关记忆衰退之间关系的纵向研究，调查老年人随后的记忆效应如何随学习任务的难度而变化的研究，另一项实验旨在验证一个假设，即在成功的情景提取过程中，老年人的神经活动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.