Opposing effects of oxytocin on moral judgment in males and females.

Current perspectives on the evolutionary roots of human morality suggest it arose to incentivize social cooperation by promoting feelings of disgust toward selfish behavior, although the underlying neural mechanisms remain unclear. To investigate whether the ancient mammalian neuropeptide oxytocin (OXT) influences self-referential processing in the domains of emotion evaluation and moral decision making, we conducted a pharmaco-functional magnetic resonance imaging (fMRI) and a behavioral experiment involving 157 healthy women and men who were treated with either OXT (24 IU) or placebo (PLC) intranasally. Our results show that OXT facilitated cortical midline responses during self-processing of disgust and selectively promoted self-interest moral judgments in men. In contrast, in women OXT increased the reaction time difference between accepted and rejected moral dilemmas and led them to suppress their self-interest and respond more altruistically for the benefit of others. Taken together, these findings suggest an OXT-related sexual dimorphism in human moral behavior which evolved adaptively to optimize both protection and nurturing of offspring by promoting selfish behavior in men and altruistic behavior in women.

Oxytocin enhances brain reward system responses in men viewing the face of their female partner.

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.

Determination of perfluorooctanoate and perfluorooctanesulfonate in water matrices by inline matrix elimination liquid chromatography with reversed phase separation and suppressed conductivity detection.

This work describes a new method for the determination of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in water matrices by suppressed conductivity detection. Separation was achieved by isocratic elution on a reversed-phase column thermostated at 45°C using an aqueous mobile phase containing boric acid and acetonitrile. The PFOA and PFOS content in the water matrix were quantified by a pre-concentration technique. For the concentration range of 1 to 15 ng/mL and 2 to 30 ng/mL, the linear calibration curve for PFOA and PFOS yielded coefficients of determination (R(2)) of 0.9995 and 0.9985, respectively. The relative standard deviations were smaller than 1.5% for PFOA and PFOS. The retention-time precision of four consecutive 12 h injections was smaller than 0.641% and 0.818%, respectively. The presence of common divalent cations, such as calcium, magnesium, and iron in water matrices impairs PFOS recovery. This drawback was overcome by applying inline matrix elimination method. The optimized method was successfully applied for drinking water, ground water, and seawater samples.