“…Several reports studying social behavior found that oxytocin (OT) and arginine-vasopressin (AVP) signaling directly impact behaviors associated with pair bonding, such as attachment, social recognition, aggression, parental care, and socio-sexual motivation ( Winslow et al, 1993 ; Williams et al, 1994 ; Insel and Hulihan, 1995 ; Insel, 1997 ; Young et al, 1998 ; Cho et al, 1999 ; Pitkow et al, 2001 ; Bales et al, 2004 ; Lim and Young, 2004 ; Lim et al, 2004 ; Olazábal and Young, 2006 ; Debiec, 2007 ; Donaldson et al, 2010 ; Smith et al, 2010 ; Keebaugh and Young, 2011 ; Cavanaugh et al, 2014 , 2015 , 2018a , 2018b ; Finkenwirth et al, 2016 ; Lieberwirth and Wang, 2016 ; Baxter et al, 2020 ; Razo et al, 2022 ). This is why the determination of OT receptor (OTR) and AVP receptor (AVPr) expression patterns in specific brain regions, and the comparison of such circuits between related monogamous and non-monogamous species, have been the standard procedure to elucidate brain regions involved in the modulation of socio-sexual monogamous behavior ( Shapiro and Insel, 1992 ; Insel et al, 1994 ; Wang et al, 1997b ; Hammock and Young, 2004 ; Smeltzer et al, 2006 ; Freeman et al, 2014 ; Freeman and Young, 2016 ; Smith et al, 2019 ).…”