In this study, we investigated the relationship between sociability and the magnitude of 5-HT1A receptor (5-HT1AR) activation-induced outward currents from layer 5 pyramidal neurons in the PFC, because a mouse model of Williams-Beuren syndrome (WBS; another developmental disorder exhibiting low innate anxiety and high sociability) reportedly showed larger 5-HT-induced currents. Here, HTR1A is linked to Williams syndrome.