An additional study investigating the effect of MAOA genotype using stop signal fMRI task in adolescent boys and girls found that MAOA was correlated with ADHD symptoms and subsequently, single-nucleotide polymorphism (SNP) rs12843268 “A” hemizygotes lowered MAOA levels and reduced ventral striatal BOLD response during monetary incentive delay task. This evidence concerns the gene MAOA and attention deficit-hyperactivity disorder.