Oxytocin enhances basolateral amygdala activation and functional connectivity while processing emotional faces: preliminary findings in autistic versus non-autistic women

Oxytocin is hypothesized to promote social interactions by enhancing the salience of social stimuli. While previous neuroimaging studies have reported that oxytocin enhances amygdala activation to face stimuli in autistic men, effects in autistic women remain unclear. In this study, the influence of intranasal oxytocin on activation and functional connectivity of the basolateral amygdala – the brain’s “salience detector” – while processing emotional faces vs. shapes was tested in 16 autistic and 21 non-autistic women by fMRI in a placebo-controlled, within-subjects, cross-over design. In the placebo condition, minimal activation differences were observed between autistic and non-autistic women. However, significant drug × group interactions were observed for both basolateral amygdala activation and functional connectivity. Oxytocin increased left basolateral amygdala activation among autistic women (35 voxel cluster, MNI coordinates of peak voxel= -22 -10 -28; mean change=+0.079%, t=3.159, ptukey=0.0166), but not non-autistic women (mean change =+0.003%, t=0.153, ptukey=0.999). Furthermore, oxytocin increased functional connectivity of the right basolateral amygdala with brain regions associated with socio-emotional information processing in autistic women, but not non-autistic women, attenuating group differences in the placebo condition. Taken together, these findings extend evidence of oxytocin’s effects on the amygdala to specifically include autistic women and specify the subregion of the effect.TLP was supported by the Autism Research Trust, Cambridge Trust, and Natural Sciences and Engineering Research Council of Canada. MVL was supported by an ERC Starting Grant (ERC-2017-STG; 755816). MCL was supported by a Canadian Institutes of Health Research (CIHR) Sex and Gender Science Chair (GSB 171373), the O’Brien Scholars Program within the Child and Youth Mental Health Collaborative at the Centre for Addiction and Mental Health (CAMH) and The Hospital for Sick Children, Toronto, the Academic Scholars Award from the Department of Psychiatry, University of Toronto, the CAMH Foundation, and the Ontario Brain Institute. SBC received funding from the Wellcome Trust 214322\Z\18\Z. For the purpose of Open Access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. SBC also received funding from the Autism Centre of Excellence, SFARI, the Templeton World Charitable Fund, the MRC, and the National Institute for Health Research (NIHR). Any views expressed are those of the author(s) and not necessarily those of the funder. RB was supported by the MRC UK, Pinsent Darwin Trust and British Academy post-doctoral fellowship