SLC6A4 and Anxiety: Furthermore, when investigating potential alterations of relevant genes in brain regions that are essential for the regulation of anxiety and social behaviors (i.e., the lateral septum and the amygdala), we found that while male partner aggression led to reduced expression of the serotonin transporter slc6a4 in the lateral septum regardless of female anxiety, male partner aggression led to reduced vasopressin receptor 1a (avpr1a) expression in the amygdala only in high anxiety females.