(A) A hypothetical model for mediation of the effect of neighborhood-level disadvantage on cognitive decline via thinning in Alzheimer disease (AD) signature cortical regions. Separate mediation models were tested for the Preclinical Alzheimer's Cognitive Composite–Revised (PACC-R) (B) and for component subtests Trail-Making Test, part B (TMT-B) (C), Story Memory Delayed Recall (SM-D) (D), and Rey Auditory Verbal Learning Test, total trials 1–5 (RAVLT-L) (E). For each mediation model, parameter estimates for total (blue), direct (red), and indirect (green) are displayed. 95% Confidence intervals were constructed using nonparametric percentile bootstrapping (10,000 iterations). The loss of cortical thickness in AD signature regions significantly mediated the effect of neighborhood-level disadvantage on the declining performance on PACC-R, subtests TMT-B and RAVLT-L, but not subtest SM-D. Significance testing of mediation model parameters: ns p > 0.1, #p < 0.1; *p < 0.05; **p < 0.01.