Oxytocin Modulates Amygdala Reactivity to Masked Fearful Eyes

Abstract

The amygdala reveals enhanced reactivity to fearful eye whites, even when they are backwardly masked by a neutral face and therefore processed with limited visual awareness. In our fMRI study, we investigated whether this effect is indeed associated with fear detection within the eyes of the neutral face mask, or more generally, with reactivity to any salient increase in eye white area. In addition, we examined whether a single dose of intranasal oxytocin would modulate amygdala responses to masked fearful eye whites via a double-blind, placebo-controlled pharmacological protocol. We found that increased amygdala responses to salient changes within a face's eye region occurred specifically for masked fearful eyes but not for similar increases in white area as induced by nonsocial control stimuli. Administration of oxytocin attenuated amygdala responses to masked fearful eye whites. Our results suggest that the amygdala is particularly tuned to potential threat signals from the eye region. The dampening effects of oxytocin on early amygdala reactivity may reflect reduced vigilance for facial threat cues at a preconscious level. Future studies may investigate whether this early modulation accounts for the beneficial effects of oxytocin on social cognition in anxiety-related disorders, as suggested by previous studies.