[1] Durham VA Healthcare Syst, Geriatr Res Educ & Clin Ctr, Durham, NC 27705 USA
[2] Duke Univ, Med Ctr, Ctr Study Aging & Human Dev, Durham, NC 27710 USA
[3] Duke Univ, Dept Psychol & Neurosci, Durham, NC USA
[4] Duke Univ, Sch Med, Dept Psychiat & Behav Sci, Durham, NC USA
[5] Duke Univ, Ctr Genom & Computat Biol, Durham, NC USA
[6] Univ Otago, Dept Psychol, Otago, New Zealand
[7] Copenhagen Univ Hosp Amager & Hvidovre, Dept Clin Res, Hvidovre, Denmark
[8] Univ Edinburgh, Sch Philosophy Psychol & Language Sci, Edinburgh, Midlothian, Scotland