Difficulty in registering and responding to facial expressions is a characteristic of autism and somr functional imaging studies claim that individuals with autism, and its very wide modern spectrum of disorders, display altered brain activations when processing facial images.

The hormone oxytocin plays a role in the social interactions of both animals and humans. Studies conducted with healthy volunteers have provided evidence for beneficial effects of oxytocin in terms of increased trust, improved emotion recognition, and preference for social stimuli.

This combinationled German researchers to hypothesize about the influence of oxytocin in autism, namely if oxytocin might promote face processing and eye contact in individuals with ASD as prerequisites for neurotypical social interaction. Dr. Gregor Domes, from the University of Freiburg and first author of the new study, says, "In the present study, we were interested in the question of whether a single dose of oxytocin would change brain responses to social compared to non-social stimuli in individuals with autism spectrum disorder."

To conduct their study, they recruited fourteen individuals with ASD and fourteen control volunteers, all of whom completed a face- and house-matching task while undergoing imaging scans. Each participant completed this task and scanning procedure twice, once after receiving a nasal spray containing oxytocin and once after receiving a nasal spray containing placebo. The order of the sprays was randomized, and the tests were administered one week apart. 

Using two sets of stimuli in the matching task, one of faces and one of houses, allowed the researchers to not only compare the effects of the oxytocin and placebo administrations, but also allowed them to discriminate findings between specific effects to only social stimuli and non-specific effects to more general brain processing.

What they found was intriguing. The data indicate that oxytocin specifically increases responses of the amygdala to social stimuli in individuals with ASD. The amygdala, the authors explain, "has been associated with processing of emotional stimuli, threat-related stimuli, face processing, and vigilance for salient stimuli".

Significant clusters showing increased activation in the bilateral fusiform gyrus (FG), amygdala (Amyg), occipital gyrus (OG), lateral temporal gyrus (lTG), medial prefrontal cortex (mPFC), and precuneus (pCun) during the discrimination of faces compared with houses in the whole group of participants (n = 28). (contrast: faces>houses). T-map with a threshold of p<.05 (familywise-error-corrected). L, left; R, right. Credit and link:
http://dx.doi.org/10.1016/j.biopsych.2013.02.007

This finding suggests oxytocin might promote the salience of social stimuli in ASD. Increased salience of social stimuli might support behavioral training of social skills in ASD.

These data support the idea that oxytocin may be a promising approach in the treatment of ASD and could stimulate further research, even clinical trials, on the exploration of oxytocin as an add-on treatment for individuals with autism spectrum disorder.

Citation: Gregor Domes, Markus Heinrichs, Ekkehardt Kumbier, Annette Grossmann, Karlheinz Hauenstein, Sabine C. Herpertz, 'Effects of Intranasal Oxytocin on the Neural Basis of Face Processing in Autism Spectrum Disorder', Biological Psychiatry Vol. 74, Issue 3, Pages 164-171 http://dx.doi.org/10.1016/j.biopsych.2013.02.007