Abstract The biological mechanisms underlying long-term partner bonds in humans are unclear. The evolutionarily conserved neuropeptide oxytocin (OXT) is associated with the formation of partner bonds in some species via interactions with brain dopamine reward systems. However, whether it plays a similar role in humans has as yet not been established. Here, we report the results of a discovery and a replication study, each involving a double-blind, placebo-controlled, within-subject, pharmaco-functional MRI experiment with 20 heterosexual pair-bonded male volunteers. In both experiments, intranasal OXT treatment (24 IU) made subjects perceive their female partner's face as more attractive compared with unfamiliar women but had no effect on the attractiveness of other familiar women. This enhanced positive partner bias was paralleled by an increased response to partner stimuli compared with unfamiliar women in brain reward regions including the ventral tegmental area and the nucleus accumbens (NAcc). In the left NAcc, OXT even augmented the neural response to the partner compared with a familiar woman, indicating that this finding is partner-bond specific rather than due to familiarity. Taken together, our results suggest that OXT could contribute to romantic bonds in men by enhancing their partner's attractiveness and reward value compared with other women.
构成人类长期伴侣联系的生物学机制目前还不清楚。在进化上保守的神经肽催产素（ OXT ） 通过脑多巴胺奖赏机制的互动从而与某些物种伴侣关系形成有关。然而，它是否在人类中起着类似作用迄今仍然未知。我们在这里表明了研究发现的结果和一项重复性研究，他们均包含有设置双盲，安慰剂对照，在内受试者，药理功能磁共振成像条件的实验，且含有20名有异性伴侣的男志愿者。在两个实验中，OXT滴鼻治疗（ 24 IU ）使受测者感觉他们女性伴侣的脸相比陌生女性来说更具有吸引力，但受测者对其他熟悉女性却没有类似感觉。这种对伴侣增强的正向偏好是与相较陌生女人来说，对伴侣刺激增加的在包含腹侧被盖区和伏隔核（NAcc）在内的大脑奖励区域内的反应相匹配的。在左侧NAcc内，相较其他熟悉女人来说，OXT甚至增加了对伴侣的神经反应，这表明这一发现由具体伴侣关系决定而并非熟悉的缘故引起的。综上所述，我们的结果表明OXT通过增强对应异性伴侣吸引力并相较其他妇女来说使男性得到奖励价值从而有助于男性维持恋爱关系。