Multiple regression analyses using the Predictive Analytics Software statistical package (PASW or SPSS, version 18, Chicago) examined how emotional neglect and the mineralocorticoid receptor genotype independently and interactively influence threat-related amygdala reactivity. We entered gender and pubertal status in the first step, followed by emotional neglect and mineralocorticoid receptor genotype in the second step, and the interaction of mineralocorticoid receptor genotype and emotional neglect in the last step. Post hoc tests were carried out in two ways (35). First, we used simple slope analyses to assess whether the association between amygdala reactivity and childhood emotional neglect was significant for each genotype group. Second, we used the Johnson-Neyman method to calculate the childhood emotional neglect values at which there were genotype differences in amygdala reactivity. In an attempt to account for background genetic differences associated with ancestral origin, we ran two additional sets of analyses. Ancestry-informative principal component variables, generated using the Eigenstrat program (36), were included in the first step of the regression. In the second, we restricted analyses to individuals reporting Caucasian ancestry (see the online data supplement). All
