A.2 Understanding Grit in healthy older adults at-risk for Alzheimer’s disease

Background: Adherence to healthy lifestyle behaviours or to prescribed medication requires perseverance with stamina, and this is captured by Grit, a non-cognitive trait defined as perseverance and passion for long-term goals. Despite predicting cognitive decline and physical, emotional, and social functioning, Grit remains poorly understood and its neural substrates are unknown in cognitive aging. Methods: Ninety-five cognitively unimpaired older adults with a family history of Alzheimer’s disease were recruited through the PREVENT-AD longitudinal cohort. Participants completed tests that assess grit and conscientiousness and underwent resting-state functional magnetic resonance imaging (fMRI). Multivariate pattern analyses (MVPA), a rigorous data-driven whole-brain approach, were used to examine if resting-state functional connectivity of connectome-wide voxels were associated with grit scores, controlling for age, sex, APOE ε4 carriership, mean displacement, and conscientiousness. Results: Our analyses identified two large (≥54 voxels) and statistically significant (p<0.01 corrected for family-wise error) clusters in the right ventrolateral prefrontal cortex and the left orbitofrontal cortex underlying grit. Conclusions: Being the first to identify functional neural correlates supporting grit in the aging population while accounting for the variance of conscientiousness, our study provides unique insights into the construct which has important applications in adherence to clinical and empirical neurological interventions as well as in successful aging.