ABSTRACT
Neuropeptide oxytocin serves as a neuromodulator in the brain and as a hormone in the body. Oxytocin as a hypothalamic hormone causes contractions during the second and third stages of labor and lets milk come out during breast feeding. As a neuromodulator, oxytocin that influences social affiliative behavior plays an important role in social cognition and emotional learning. Recent studies showed that oxytocin affects basic fear learning and fear extinction precess in a social context. Furthermore, oxytocin has anxiolytic and stress-dampening effects when combined with social support, i.e. a safety stimuli. Also, oxytocin enhances basic emotional learning precesses of both acquisition and extinction of an emotional content while simultaneously decreasing pain experiences. Oxytocin has involvement in attachment, and is shown to improve positive affective behavior in romantic relations. Social buffering effects that social touch and emotional and physical intimacy play crucial roles in coping with negative effects are assumed to be mediated through brain oxytocin mechanisms. Researches indicate that oxytocin significantly inhibits hypothalamic-pituitary-adrenal axis activity in response to stress, and consequently reduces cortisol levels. Conversely, exposure to stress triggers the release of intrahypothalamic and plasma oxytocin. These results suggest that oxytocin may be a new pavement in treating post-traumatic stress disorder and depression.