Oxytocin Attenuates Neural Reactivity to Masked Threat Cues from the Eyes

Abstract

The neuropeptide oxytocin has recently been shown to modulate covert attention shifts to emotional face cues and to improve discrimination of masked facial emotions. These results suggest that oxytocin modulates facial emotion processing at early perceptual stages prior to full evaluation of the emotional expression. Here, we used functional magnetic resonance imaging to examine whether oxytocin alters neural responses to backwardly masked angry and happy faces while controlling for attention to the eye vs the mouth region. Intranasal oxytocin administration reduced amygdala reactivity to masked emotions when attending to salient facial features, ie, the eyes of angry faces and the mouth of happy faces. In addition, oxytocin decreased neural responses within the fusiform gyrus and brain stem areas, as well as functional coupling between the amygdala and the fusiform gyrus specifically for threat cues from the eyes. Effects of oxytocin on brain activity were not attributable to differences in behavioral performance, as oxytocin had no impact on mere emotion detection. Our results suggest that oxytocin attenuates neural correlates of early arousal by threat signals from the eye region. As reduced threat sensitivity may increase the likelihood of engaging in social interactions, our findings may have important implications for clinical states of social anxiety.

Oxytocin Modulates Amygdala Reactivity to Masked Fearful Eyes

“…This finding concurs with a recent study's data showing that oxytocin attenuates amygdala responses to threat cues from the eye region at very early stages of emotion perception (Kanat et al, 2015). In addition, oxytocin reduced the reactivity of the pulvinar, anterior cingulate cortex, and parts of the ventral stream to salient changes within the eye region on the neutral face mask irrespective of emotional meaning.…”

“…Furthermore, we examined whether a single dose of intranasal oxytocin would modulate responses of the amygdala and associated brain structures to masked fearful eye whites by means of a double-blind, placebo-controlled pharmacological protocol. As previous studies reported dampening oxytocin effects on amygdala reactivity to facial threat in men (Domes et al, 2007a;Kanat et al, 2015;Kirsch et al, 2005;Petrovic et al, 2008), we expected decreased amygdala responses to fearful eye whites following oxytocin as compared with placebo administration.…”

“…Notably, oxytocin's effects on both facial emotion processing and eye gazing behavior seem to be mediated via the amygdala (Gamer et al, 2010; for a recent review, see Kanat et al, 2014) and to occur very early during stimulus perception (Kanat et al, 2015;Schulze et al, 2011). In a recent study, we showed that intranasal oxytocin specifically reduces amygdala responses and its functional coupling with visual cortex areas when attending to cues from the eye region signaling social threat even when awareness of these cues is largely restricted (Kanat et al, 2015).…”

“…Evidence from eye tracking studies points to a valencedependent modulation of eye gazing behavior by oxytocin with increased orientation to the eye region on neutral and positive faces (Domes et al, 2013b;Gamer et al, 2010;Guastella et al, 2008), but decreased attentional capture by threatening eye cues (Domes et al, 2013b). Notably, oxytocin's effects on both facial emotion processing and eye gazing behavior seem to be mediated via the amygdala (Gamer et al, 2010; for a recent review, see Kanat et al, 2014) and to occur very early during stimulus perception (Kanat et al, 2015;Schulze et al, 2011). In a recent study, we showed that intranasal oxytocin specifically reduces amygdala responses and its functional coupling with visual cortex areas when attending to cues from the eye region signaling social threat even when awareness of these cues is largely restricted (Kanat et al, 2015).…”

Oxytocin and Serotonin Brain Mechanisms in the Nonhuman Primate

“…Although this is consistent with our study in humans, lateralization is not commonly observed in macaques, and this finding deserves further research. Such lateralization is often observed in fMRI-OT studies with humans (Domes et al, 2007;Kanat et al, 2015) but hard to interpret, especially because other studies have also found left lateralization (Kirsch et al, 2005). To increase the repeatability of our experiment and reduce brain damage caused by the needle, we always injected OT or PLA at the same location in the right hemisphere.…”