Chunk #26 — MATERIALS AND METHODS — Neural extension II: Reward-related functional magnetic resonance imaging analyses of GWS loci in the Duke Neurogenetics Study
We examined whether GWS loci identified in analyses of alcohol-related phenotypes were associated with reward-related brain function among non-Hispanic AA (n=118; 72% female, 19.6 ± 1.2 years of age) and EA (n=481; 54.5% female, 19.8±1.2 years of age) undergraduate students who completed the Duke Neurogenetics Study (DNS; 25; see Supplemental Text). For rs7597960, which was unavailable in DNS imputed data, we used a proxy SNP, rs2418646, which is in complete LD (i.e., r2=1.0, D’=1.0) within those of African and European ancestries. The chromosome 8 and 15 loci were unavailable in DNS imputed data and no proxies were available; due to their low MAFs, they were difficult to impute in this smaller sample. A number guessing paradigm was used to elicit ventral striatum (VS) reactivity associated with positive and negative feedback linked to monetary gains and losses while blood-oxygen-level dependence (BOLD) functional magnetic resonance imaging (fMRI) data were acquired 48. Statistical Parametric Mapping version 8 (SPM8) software was used to extract parameter estimates for the contrast of Positive Feedback > Negative Feedback from maximal voxels within left and right VS regions
