Furthermore, although many studies found a significant negative correlation between depressive symptoms and oxy-Hb concentrations in the left DLPFC and LOFC using fNIRS (Shajahan et al., 2002; Zhong et al., 2011; Mannie et al., 2011; Speer et al., 2009; Ong et al., 2021), other studies have observed no significant correlations (Tsujii et al., 2014) or even a significant positive association (Liu et al., 2014) between depression scores and oxy-Hb concentrations. The gene discussed is GSTM1; the disease is major depressive disorder.