INVESTIGATING AGE-RELATED DIFFERENCES IN COGNITIVE AND NEURAL REPRESENTATIONS IN ASSOCIATIVE MEMORY

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Older adult memory is vulnerable to an associative deficit – a decline in the ability to link together multiple pieces of information. This has implications for many aspects of cognitive functioning in everyday life, such as remembering to take medicine at a certain time of day. However, not enough is known about the neural bases of the associative deficit. For example, how does the associative deficit fit into broader theories of the functional organization of memory networks in the human brain, and how is the associative deficit linked to age-related changes in neural representations of information? The long-term goal of the proposed research is to gain understanding of associative memory mechanisms in aging so that beneficial intervention strategies for memory can be developed for use with older adults. The objective of the current research is to test whether specific age- related differences in associative memory can be accounted for by differences in neural specificity and functional connectivity in posterior-medial and anterior-temporal cortico-hippocampal networks. The overarching hypothesis is that the associative deficit depends on the degree to which neural specificity and functional connectivity each contribute to a task. The rationale for the proposed research is that investigating age-related differences in neural representations and functional connectivity in associative memory will lead to a more robust theory of the associative deficit, and will enable the development of methods for presenting information to older adults in ways that reduce age differences in associative memory. Innovative fMRI experiments are proposed that will: 1) Examine how encoding of new associations is affected by age differences in reactivation and processing of prior associations and in the dynamics of cortico-hippocampal networks; and 2) Investigate how dedifferentiation in perceptual regions contributes to age differences in the encoding and retrieval of associations within cortico-hippocampal networks for memory. The approach is innovative because the planned experiments will combine novel experimental designs with advanced fMRI analysis methods to bridge the gap between cognitive theories of the associative deficit and underlying neural differences between young and older adults. The proposed research is significant because results of the studies will generate new insights in scientific understanding of the neural bases of the associative deficit. This work represents a critical step toward a unified explanation of associative memory deficits in aging. It will advance the field of aging and memory as well as enable the development of interventions, such as more effective means of presenting information, that may improve information representations in associative memory, thereby improving health and quality of life.