BOLD responses within each a priori ROI (left and right mPFC, vmPFC) were tested in a Genotype(2) × Odor(2) × Condition(2) linear mixed-effects model in which Genotype represented GABRA2 SNP genotype (AA, AG), Odor represented AO and ApCO, and Condition represented alcohol or saline (placebo) infusion. All regions showed significant main effects of Odor (left mPFC, F= 12.481,99, p = 0.001; right mPFC, F= 6.481,34, p< 0.05; left vmPFC, F= 17.011,99, p < 0.001; right vmPFC, F= 6.531,99, p < 0.05) reflecting a larger BOLD response to AO than ApCO (Figure 3a). The only region in which there was a significant Condition effect was the right mPFC (F= 6.081,35, p < 0.05), where the odorant response (combined AO and ApCO contrasted against odorless sniffing) was larger during placebo (mean BOLD contrast 0.66, SD=1.74) than during alcohol infusion (0.00, SD= 1.42). However, Condition did not interact with Odor class (indicating that alcohol did not influence AO and ApCO differentially) or with group (indicating that the alcohol effect was equal across genotypes on the general odorant response).
