ABSTRACTOxytocin(OT) has effects in both human behavior and in the brain, which is not limited in the specific brain area but also with the potential effect on connectivity with other brain regions. Evidence indicate that the effects of OT on human behavior are multifaceted, such as trust behavior, decrease anxiety, empathy and bonding behavior. Since the vital role of mentalizing in understanding others, here we proposed and tested that whether OT has a general effect on theory of mind brain

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... twork which is associated to the effect of related social behavioral and personality traits. Used a randomized, double-blind placebo-controlled group design, we investigated the resting-state functional magnetic resonance imaging after intranasal OT or placebo. The functional connectivity (FC) maps with seed in left temporoparietal junction (lTPJ) and right TPJ showed that OT significantly increased connectivity between rTPJ and default attention network (DAN), while decreased the FC between lTPJ and medial prefrontal network (MPN). With implementing machine learning approach, we further reported satisfactory classification accuracy that Identified altered FCs of TPJ can classify OT and PL group. Moreover, individual's empathy trait can modulate the FC between left TPJ and right RECT, which was positively correlated with empathic concern in PL group whereas lTPJ-rRECT negatively correlated in OT group. These results demonstrate that OT has significant effect on FC with lTPJ and rTPJ, brain regions critical for mentalizing, and the empathy concern can modulate the FC. These findings add to our understanding of the neural mechanisms by which OT modulates social behaviors, especially in social interaction involving mentalizing.