Oxytocin reduces neural activation in response to infant faces in nulliparous young women

Abstract

Infant faces have distinctive features that together are described as baby schema, a configuration that facilitates caregiving motivation and behavior, and increases the perception of cuteness. In the current functional magnetic resonance imaging (fMRI) study, we investigated the effect of a within-subjects intranasal oxytocin administration (24 IU) and caregiving motivation on neural responses to infant faces of varying baby schema in 23 healthy nulliparous women. Overall, infant faces elicited activation in several brain regions involved in reward and salience processing, including the ventral tegmental area (VTA), putamen, amygdala, anterior cingulate cortex (ACC), and insula, and this activation was related to self-reported caregiving motivation. Critically, whereas we hypothesized enhanced neural caregiving-related responses after oxytocin administration, we observed reduced activation in the VTA, putamen and amygdala after oxytocin compared to placebo. In nulliparous women, oxytocin has been shown to reduce neural responses in the same regions in response to social stimuli using other paradigms. Oxytocin might affect neural activation toward social stimuli depending on elicited arousal and personal characteristics. The current study is the first to demonstrate this effect in response to infant faces and thereby adds to specify the role of oxytocin in human social information processing.

Fig. 1

A, Axial slices with corresponding Y-coordinates (MNI) from the T-map of neural activation of all infant faces vs rest overlaid onto a standard anatomical template. B, Coronal slices with corresponding X-coordinates (MNI) from the T-map of neural deactivation toward all infant faces for oxytocin vs placebo, depicting significant deactivation in the VTA (right) and putamen (left). C, Coronal slices with corresponding X-coordinates (MNI) from the F-map of the effect of cuteness condition of the stimuli in both administration conditions. Significant modulation by cuteness was observed in the VTA (right) and amygdala (left). For the VTA, putamen and amygdala bar graphs of the parameter estimates extracted from anatomical bilateral ROIs in all conditions vs rest are displayed. Accompanying statistics are described in the text. All statistical maps are thresholded at P = 0.001 uncorrected, for illustration purposes only. Non-thresholded statistical maps of the main fMRI analyses can be found at the NeuroVault data repository (http://neurovault.org/collections/3699/).

Fig. 2

Scatterplots of the correlations between extracted parameter estimates from the anatomical bilateral putamen toward all infant stimuli and participants score on the PCAT-n. The left panel shows the significant correlation in the placebo condition (r = 0.60, P = 0.003), which was absent after OXT administration (r = 0.30, P = 0.16).