Effect of aging on item and context memory, neural function, and neural structure

描述（由申请人提供）：健康老年人的记忆缺陷很可能是内侧颞叶（MTL）结构和前额叶皮层（PFC）衰退的结果。不同类型信息的记忆（项目与上下文信息）可能依赖于MTL和PFC的不同区域，并且可能受到年龄的不同影响，尽管神经生物学证据不足。此外，尚不清楚PFC和MTL在灰质、白质或两者结合中的变化是否更强烈地影响年龄对记忆的有害影响。使用一种新颖的实验范式，年轻人和老年人将研究白色背景上的物体和丰富视觉环境中的物体。在进行功能性磁共振成像（fMRI）时，参与者将接受记忆测试，以评估物体识别、偶然检索上下文信息和有意检索上下文信息。为了评估大脑白质的完整性，参与者还将接受弥散张量成像（DTI）。老年人将接受一系列旨在评估记忆和执行功能的神经心理学测试，测试结果将用于研究fMRI激活模式、白质完整性以及项目和情境记忆的个体差异。因此，该项目将是第一个研究健康老年人项目和情境记忆（偶然的和有意的）、白质完整性、功能激活模式和神经心理状态之间关系的研究之一。阐明健康老年人的记忆和神经功能与年龄相关的变化，对于开发有助于早期发现破坏性痴呆疾病（如阿尔茨海默病和脑血管病）的范式至关重要。疾病过程的早期发现可以导致早期干预，以尽量减少患者的记忆衰退，延长自主权，并减轻照顾者的负担。然而，首先有必要阐明健康老年人记忆的神经相关性，以便人们可以发现正常衰老和前驱疾病过程之间的细微差异。本项目旨在全面评估与年龄相关的记忆和神经结构和功能的变化，并为未来临床研究提供经验基础，旨在评估干预对fMRI和DTI测量的记忆功能和神经完整性的影响。

DESCRIPTION (provided by applicant): Memory deficits in healthy older adults are most likely a consequence of decline in medial temporal lobe (MTL) structures and prefrontal cortex (PFC). Memory for different types of information (item versus context information) may rely on various regions within MTL and PFC, and may be differentially impacted by aging, although neurobiological evidence is scare. Furthermore, it is unclear whether PFC and MTL changes in grey matter, white matter, or a combination, more strongly influence the deleterious effect of age on memory. Using a novel experimental paradigm, young and older adults will study objects on a white background and objects in a rich visual context. While undergoing functional Magnetic Resonance Imaging (fMRI), participants will receive a memory test that will assess object recognition, incidental retrieval of contextual information, and intentional retrieval of contextual information. To assess white matter integrity in the brain, participants will also undergo Diffusion Tensor Imaging (DTI). Older adults will receive a comprehensive battery of neuropsychological tests designed to assess memory and executive function, the results of which will be used to investigate individual differences in fMRI activation patterns, white matter integrity, and item and context memory. Thus, the project proposed will be one of the first studies to investigate the relationship between item and context memory (incidental and intentional), white matter integrity, functional activation patterns, and neuropsychological status in healthy older adults. Elucidation of age-related changes in memory and neural function in healthy older adults is critical to the development of paradigms that will facilitate early detection of devastating dementing illnesses such as Alzheimer's disease and Cerebrovascular Disease. Early detection of disease processes could lead to early intervention to minimize memory decline in patients, prolong autonomy, and reduce caregiver burden. However, it is first necessary to elucidate neural correlates of memory in healthy older adults so that one may detect subtle differences between normal aging and prodromal disease processes. The proposed project aims to provide a comprehensive assessment of age-related changes in memory and neural structure and function, and could provide an empirical foundation for future clinical studies aimed at assessing the efficacy of intervention in memory function and neural integrity as measured by fMRI and DTI.