Neurophysiological effects of acute oxytocin administration: systematic review and meta-analysis of placebo-controlled imaging studies

Background: Oxytocin (OXT) plays a prominent role in social cognition and may have clinical applications for disorders such as autism, schizophrenia and social anxiety. The neural basis of its mechanism of action remains unclear. Methods: We conducted a systematic literature review of placebo-controlled imaging studies using OXT as a pharmacological manipulator of brain activity. Results: We identified a total of 21 studies for inclusion in our review, and after applying additional selection criteria, 11 of them were included in our fMRI voxel-based meta-analysis. The results demonstrate consistent alterations in activation of brain regions, including the temporal lobes and insula, during the processing of social stimuli, with some variation dependent on sex and task. The meta-analysis revealed significant left insular hyperactivation after OXT administration, suggesting a potential modulation of neural circuits underlying emotional processing. Limitations: This quantitative review included only a limited number of studies, thus the conclusions of our analysis should be interpreted cautiously. This limited sample size precluded a more detailed exploration of potential confounding factors, such as sex or other demographic factors, that may have affected our meta-analysis. Conclusion: Oxytocin has a wide range of effects over neural activity in response to social and emotional processing, which is further modulated by sex and task specificity. The magnitude of this neural activation is largest in the temporal lobes, and a meta-analysis across all tasks and both sexes showed that the left insula demonstrated the most robust activation to OXT administration.