Oxytocin and the Processing of Social Stress-Associated Chemosignals

Social transmission of stress and fear is not restricted to visual or auditory cues, but extends to the olfactory domain, a phylogenetically more ancient sense. Exposure to axillary sweat from healthy volunteers undergoing an emotional stressor task evokes a strong vicarious stress response on the behavioral and neural level.Particularly, anxious individuals have been shown to exhibit a heightened sensitivity to social chemosensory stress cues (axillary sweat). The neuropeptide oxytocin (OXT) exerts anxiolytic and anti-stress effects in visual and auditory modalities, however, it still elusive whether OXT also modulates the processing of stress-associated chemosignals. Axillary sweat were obtained from an unrelated sample of 30 healthy men undergoing the Trier Social Stress Test and ergometer training as control.Subsequently, subjects completed a forced-choice emotional face recognition task composed of stimuli with varying intensities (neutral to fearful), while they were exposed to both sweat stimuli and a non-social control odor (raspberry) after OXT or placebo administration, respectively. The investigators expect that OXT selectively diminishes chemosensory-induced behavioral biases and neural responses to stress-related odors.