The CA2 is highly expressed with the vasopressin 1b (Avpr1b) receptor (Young et al., 2006), and the knockout of Avpr1b results in social memory impairment (Wersinger et al., 2002; DeVito et al., 2009), whereas targeted activation of CA2 Avpr 1b during the acquisition period could enhance social memory (Smith et al., 2016), demonstrating their association. The gene discussed is AVPR1B; the disease is memory impairment.