The Effect Of Oral Oxytocin On Emotional Processing In Both Sexes

The ability to accurately recognize and comprehend oneself and others’ emotions,also known as emotional processing,is paramount for individuals in managing diverse social interactions.The oxytocin system’s proper function ensures the normal operation of social and emotional functions in individuals.It not only severely impairs an individual’s social cognitive and emotional functioning,but may also increase the risk of a variety of neurodevelopmental and psychiatric disorders if the system was impaired,including but not limited to autism spectrum disorders,anxiety disorders,depression,and post-traumatic stress disorder.Recent studies have found that the oral route can also produce a similar effect,and this way of intake is more acceptable.Therefore,current study used oral administration of oxytocin,combined with behavioral measurement,psychological measurement,biological measurement,and functional magnetic resonance imaging(f MRI)technology,to explore the influence of oxytocin on the processing of emotions.Given that previous studies have suggested gender differences in behavioral and neural responses during emotional processing,which may be one of the reasons for the gender differences in the prevalence of many developmental-related mental disorders.Meanwhile,most previous oxytocin studies have included data from male subjects,few studies have included data from females and directly compared the effects of oxytocin on emotional processing in both sexes.Therefore,current research recruited 160 healthy college students(80 females),combined with f MRI technology,to comprehensively investigated the modulation effects of oral oxytocin on emotional face processing(study1),emotional scene processing(study 2)and spontaneous neural activity(study 3)of both sexes through three studies,as well as the effects on hormone levels(oxytocin concentrations).The details are as follows:Study 1 final analyzed 145 healthy college students(75males,70 females).A randomized,double-blind placebo-controlled between-subjects design pharmacological f MRI experiment was conducted to investigate how oral oxytocin influences the disparity in emotional facial expression processing between sexes via the implicit emotional faces(happy/neutral/angry/fearful)f MRI task and the post-scan emotional faces rating task(valence/intensity/arousal).Results show that oral oxytocin selectively enhanced neural responses of left amygdala to happy and angry faces in females compared to males,and had a significant stronger increasing effect on the right putamen-right superior temporal gyrus functional coupling during happy faces processing in females.Overall,study 1suggests that oral oxytocin increases responses reward and emotional processing systems to emotional faces in both sexes,and oxytocin produced more extensive effect on females’ s amygdala.To further explore the effects of oral oxytocin on emotional processing,study 2examined the sex-regulating effects of oral oxytocin on neural activity elicited by continuously presented emotional scene stimuli with complex context and information.Study 2 included data from 147 healthy college students(73 males and 74 females)using similar experimental design as study 1,it combined an implicit emotional scenes(positive/neutral/negative)f MRI task with the post-scan emotional scenes rating task(valence/intensity/arousal)to examine the impact of orally administered oxytocin on the differences in emotional scene processing between males and females as well as the regulating effect of it on plasma oxytocin concentration.Results showed that females have significant lower endogenous plasma oxytocin concentrations compare to males,but oral oxytocin equally increased oxytocin concentrations in both sexes.Under placebo conditions,the right amygdala response to emotional scenes was significantly higher in females relative to males.Oral oxytocin enhanced the right amygdala response in males but reduced it in females.Meanwhile,oral oxytocin attenuated the strength of the right amygdala-left insula functional coupling during emotional scenes processing in males,but not in females.Multivariate pattern analysis further revealed an emotional processing network,including the right amygdala and left insula,could effectively classify neural patterns of emotional scene processing between two sexes,but oral oxytocin decreased the classify performance of this network.Overall,oral oxytocin attenuate sex differences in neural responses of emotional processing network to emotional scenes.This finding may reflect that oxytocin could enhance the unconsciously regulation ability to emotional scenes for both sexes via promotes appropriate changes in sex-specific amygdala-insula circuitry.Study 3 ultimately analyzed the resting-state data from 153 healthy college students(75 males and 78 females).Initially,based on the results of the first two studies,seedbased functional coupling analyses with the amygdala as seed regions were conducted to investigate the sex-modulating effects of orally administered oxytocin on spontaneous functional coupling of the amygdala.Secondly,exploratory correlation analyses were conducted to examine the baseline levels of endogenous oxytocin and its correlation with high-risk traits for mental disorders.Finally,correlation analyses were further conducted to investigate the modulatory effect on the high-risk traits for mental disorder-related amygdala’s functional coupling.The results revealed that under the placebo condition,the strength of functional coupling between the left amygdala and the left insula,as well as between the right amygdala and the left medial prefrontal cortex,was significantly higher in females than in males.Furthermore,oxytocin significantly reduced the strength of these functional connections in females while enhancing them in males.Exploratory correlation analysis revealed a significant negative correlation between endogenous oxytocin concentrations and autism traits as well as childhood trauma experience scores.Besides,correlation analysis also revealed that oral oxytocin can modulate the correlation between the amygdala-precentral functional coupling and childhood trauma experiences in both males and females.This may indicate that oxytocin can improve stress adaptability and handling ability of individual in adversity via facilitate appropriate changes in the amygdala-precentral circuitry.In summary,current study systematically revealed the modulatory effects of oral oxytocin on the emotional processing in both sexes.Firstly,this study revealed the modulatory effects of oral oxytocin on brain regions related to emotional processing in both sexes.Second,this study shows that oral oxytocin modulates the activity of emotional processing circuits associated with stress adaptation.This finding provides experimental evidence supporting the potential use of oral oxytocin as an adjunctive intervention for psychiatric and neurodevelopmental disorders associated with social functioning and emotional processing impairments.