Objectives: Recent studies suggest that single dose intranasal oxytocin lead to enhance emotional recognition and increase eye gaze, and intranasal oxytocin is a promising candidate treatment of social impairments of patients with autism spectrum disorder (ASD). Neuroimaging studies also identified that single dose intranasal oxytocin changed brain activation in medial prefrontal cortex (MPFC), middle frontal gyrus (MFG), and amygdala during social cognition processing in individual with ASD. However, to date, there have been no attempts to investigate the effects of long-term intranasal oxytocin of daily administration. In the current study, we tested the effect of long-term intranasal oxytocin on the resting-state functional connectivity (rs-FC) with the default mode network (DMN).
Methods: In a randomized, double-blind, placebo-controlled clinical trial, ten individuals with ASD received intranasal oxytocin or placebo. Resting-state functional MRI before and after long-term oxytocin administration were used to investigate the alteration of rs-FC with DMN. Repeated measures analysis of variance (ANOVA) was applied to identify brain regions exhibiting a predicted treatment Χ time interaction.
Results: The result of ANOVA shows interaction between treatment and time in rs-FC between angular gyrus with anterior medial prefrontal cortex (aMPFC). We also found the degree of change of rs-FCs between angular gyrus with aMPFC are associated with Clinical Global Impressions - Improvement (CGI-I) scales.
Conclusion: These findings reveal a unique process underlying the effects of long term intranasal oxytocin. Interestingly, these regions largely overlap with the language and semantic processing. This is the first evidence of the effects of long-term intranasal oxytocin administration on communication within social cognition processing.