OXTR and Anxiety: Despite the abundant evidence across species of the interaction between the OXT and 5HT systems in the regulation of socio-cognitive behaviors (Lefevre et al., 2017; Nagano et al., 2018; Tan et al., 2020), anxiety (Yoshida et al., 2009), and reward (Aubert et al., 2013; Dölen et al., 2013), only one recent report has provided evidence of the existence of a 5HT2AR–OXTR heterodimer, which was detected in in rat hippocampus, cingulate cortex, and NAcc, key regions associated with cognition and the above-described behaviors (Chruścicka et al., 2019).