In the familiar face condition, the Z-scores for oxy-Hb concentrations in the ADHD boys were significantly increased in both temporal cortices in the early phase: right temporal cortex; t (8) = 3.80, p = 0.005; left temporal cortex; t (8) = 2.79, p = 0.023. This evidence concerns the gene GSTM1 and attention deficit-hyperactivity disorder.