To better understand the direction of influence between nodes (i.e., A→B vs. B→A), we conducted pairwise LiNGAM analyses on links observed in the NBS analyses between cortical and subcortical structures. No links evidenced a significant mean direction of influence. However, the externalizing PS significantly moderated the direction of influence for two links, and these effects survived FDR correction. Specifically, higher polygenic risk was associated with a greater direction of influence from left amygdala→left IFG pars triangularis (p = .007 [corrected p = .033]) and from right amygdala→left IFG pars triangularis (p = .013 [p = .033]). This suggests that bilateral amygdala is influencing left IFG triangularis in participants with stronger polygenic associations with externalizing, whereas the opposite is true in those with weaker polygenic associations with externalizing.
