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.
