The Seattle Longitudinal Study has been funded by grants from the National Institute of Child Health and Human Development (HD 00367, 1963-65; HD-04476, 1970-73) and by the National Institute on Aging (AG00480, 1973-79; AG03544, 1982-86; AG04770, 1984-89; R37 AG08055, 1989-2006; AG R03 AG009787, 2006-09; R37 AG024102 2005-15). 

The Midlife study, which continues the Seattle Longitudinal Study, has been funded by a grant from the National Institute on Aging (R37 AG024102, 2006-2015). In this study, 1207 participants in the SLS were assessed once more in an eighth wave, picking up where the SLS left off. The midlife study asssesses impact of midlife changes from 46 to 60 upon cognitive performance in old age. Of the approximately 800 participant who have been studied in midlife, almost 200 participants' brains have been studied by the non-invasive methods of structural and functional MRI.