Oxytocin Modulation of Startle Reactivity to Social Stimuli and Moral Decision Making

Double-blind, Placebo-controlled, Randomized Study: Oxytocin Modulation of Startle Reactivity to Social Stimuli and Moral Decision Making

The purpose of this study is to determine whether oxytocin affects the modulation of startle reactivity by aversive social stimuli and to investigate the oxytocin effect on moral judgements. Furthermore the investigators explore the effects of oxytocin receptor (OXTR) polymorphisms on behavioral responses to social stimuli.

The neuropeptide oxytocin (OXT) can enhance the impact of positive social cues but may reduce that of negative ones, although it is unclear whether the latter causes blunted emotional responses. After OXT or placebo application participants are exposed to acoustic startle probes presented alone and during viewing of 60 color pictures mostly selected from the 'International Affective Picture System'. The paradigm featured 20 negative (mostly threatening), 20 neutral, and 20 positive pictures, presented for 5 s each. In the other part of the experiment, after intranasal OXT or placebo application participants respond to 60 moral dilemmas.

Inclusion Criteria:

• Healthy male volunteers

Exclusion Criteria:

• Current or past psychiatric disease
• Current or past physical illness
• Psychoactive medication
• Tobacco smokers