PROJECT SUMMARY/ABSTRACT We seek to compare genetic/lifestyle interactions between African Americans and Nigerian Yoruba, using novel cognitive assessments of generalization developed at Rutgers, while linking individual differences in cognitive function on these tasks to variations in candidate genes. A majority of African American descendants of slaves have their ancestry (and hence, genetic variations) linked to the Yoruba people of West Africa. Understanding the similarities and differences in the interactions between genetic and lifestyle variations influencing MTL-specific cognition in older African Americans and older Yoruba will further illuminate complex determinants of AD risk and progression. This one year administrative supplement seeks to cross-validate current findings on risks of Alzheimer’s disease (AD) in African Americans with a different but similar and related population cohort—Yoruba people of West Africa by addressing a key question: Are African Americans and Yoruba people similar in their behavioral and neural risk markers for AD, specifically with regard to interactions between genetics (especially APOE and ABCA7) and modifiable health and lifestyle factors, especially physical fitness. With this supplemental funding we will expand the parent grant methods to collect blood from (a) 120 cognitively-healthy (non-demented) Yoruba, ages 60 and above, recruited at the University of Ibadan, and (b) compare genetic/lifestyle interactions between African Americans and Nigerian Yoruba, using novel cognitive assessments developed at Rutgers. The initial cross-sectional analysis will compare genetic/lifestyle interactions between African Americans and Nigerian Yoruba, using novel cognitive assessments of generalization developed at Rutgers, while linking individual differences in cognitive function on these tasks to variations in candidate genes. This will lead up to the longitudinal analysis (R01) assessing broader root causes of the high rates of cognitive decline and AD progression in older people of African ancestry.