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Exploring brain system segregation as a neural mechanism of cognitive reserve in bilingualism.

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Tyler M. Call¹ (tylercall@cmail.carleton.ca), John G. Grundy², John A.E. Anderson¹; ¹Carleton University, ²Iowa State University

Bilingualism is associated with a delay in the onset of Alzheimer’s dementia symptoms of approximately four years. Thus, it is hypothesized that bilingualism provides reserve, i.e., resilience to age-related and pathological brain degeneration. While bilingualism does have significant effects on brain structure, these measures do not fully explain individual differences in cognitive performance. The construct of cognitive reserve is intended to capture this unexplained variance. Recently, the search for neural mechanisms of cognitive reserve has focused on the connectivity of functional brain networks. One functional connectivity metric, brain system segregation, has been shown to predict cognitive performance independent of age. Brain system segregation also declines with age, and this change is strongly correlated with age-related cognitive decline. One recent study has demonstrated two intriguing findings: first, that higher levels of education are associated with preserved brain system segregation longitudinally; and second, that preserved brain system segregation predicts clinical dementia outcomes over and above structural and pathological measures. However, brain system segregation has not been used to investigate the neural mechanisms of cognitive reserve in bilingualism. In this poster, we explore the relationships between bilingualism, brain system segregation, and cognitive outcomes using data from the Alzheimer’s Disease Research Initiative. Bilingualism is assessed in terms of self-reported proficiency and usage data, and brain system segregation metrics are derived from resting-state functional magnetic resonance imaging data.

Topic Area: THINKING: Development & aging