The Influence Of Estrogen Hormones On Disgust Processing

As one of the most basic emotions of humans and animals,disgust is an emotion to avoid potential disease and moral transgressions which is often accompanied by nausea,vomiting,and a strong desire to stay away from elicitors.According to the elicitors,disgust can be divided into pathogen disgust and moral disgust.According to the elicitors,disgust can be divided into pathogen disgust and moral disgust.Pathogen disgust is evoked by objects that carry pathogen cues such as bacteria,viruses or parasites.Moral disgust is usually evoked by behaviors or characters that violate social moral norms and codes of conduct,which originates from pathogen disgust.Pathogen disgust and moral disgust have similar subjective experiences,facial expressions,and behavioral responses,but also have different processes.Compared with men,women are characterized by higher disgust sensitivity,a stronger sense of disgust experience,greater avoidance behavior,and physiological response when they face disgust elicitors.This unique advantage may be related to certain hormones of females.Studies have shown that the production and expression of disgust are affected by a variety of hormones,including estrogen,progesterone,oxytocin,testosterone,corticosteroids,and so on.These different neuroendocrine regulatory systems enable people to focus on pathogen cues,on this basis,the assessment is integrated to produce disgust response.The higher levels of estrogen hormones in females may have an important role in disgust processing.Thus,this study will explore the effects of the two most common types of gonadal hormones(estrogen and progesterone)in women on disgust processing.Through three studies with five experiments,the effects of estrogen and progesterone on pathogen disgust and moral disgust were explored,and brain mechanism was explored from the perspective of endogenous ovarian hormones changes and exogenous estrogen administration.This research combined with behavioral research and brain imaging research,using implicit and explicit processing methods with phrase stimulation as materials.Study 1consisted of two behavioral experiments,which used the single category implicit association test(SC-IAT)and disgust intensity scoring task respectively.Using the regular fluctuations of endogenous estrogen and progesterone in the menstrual cycle as a cut-off,it explored the differences between processing pathogen disgust and moral disgust in women during menses,follicle,and luteal phases.In the SC-IAT,the results showed that the D value of two kinds of disgust during the luteal phase was significantly higher than that during the follicular phase and the menses phase,but there was no significant difference between the follicular phase and the menses phase.In the disgust intensity scoring task,it was found that the effect of the menstrual cycle on the subjective experience of disgust stimuli was moderated by stimulus intensity.Only in the low-intensity stimulus,the intensity of pathogen disgust perceived by women in the follicular phase was significantly lower than that in the menses phase and luteal phase,while there was no significant difference in moral disgust during the three phases.In terms of reactiontime scoring,it was found that compared with the menses phase and the luteal phase,women in the follicular phase had a longer response time to pathogen disgust phrases,while there was no significant difference in moral disgust phrases,indicating that the response time of the follicular phase to the pathogen disgust stimulus was slower than that of the menses phase and the luteal phase.A more negative attitude toward disgust stimuli in the luteal phase may be related to high progesterone levels,and low disgust perception in the follicular phase may be associated with high estrogen levels.Study 2 used acute estradiol administration to explore the effects of estradiol on processing disgust in menstrual women,using the same experimental paradigm as in Study 1.In the SC-IAT,no significant difference in D values was found between the estradiol-administered and placebo groups.In the disgust intensity scoring task,for pathogen disgust,there was no significant difference between the estradiol group and the placebo group in the pretest,but the estradiol group was significantly lower than the placebo group in the posttest.As for moral disgust,there was no significant difference between the estradiol group and the placebo group in the pretest,but the estradiol group was significantly lower than the placebo group in the posttest.The finding suggested that acute estradiol administration reduced the subjective disgust intensity of pathogen and moral disgust stimuli in women during the menses phase,but it did not change the implicit attitude towards either type of disgust stimuli.Study 3 used the disgust intensity score task and fMRI technology to scan women while processing disgust at the three phases of menstruation respectively,which initially explored the brain mechanisms by which estrogen and progesterone affect disgust.The results revealed that compared with the menses phase,the follicular phase had less activation of the anterior cingulate gyrus,the right orbital upper frontal gyrus,the right wedge lobe,and the right occipital gyrus during pathogen disgust processing.Besides,the left anterior cingulate,the medial upper frontal gyrus of the left brain and the upper frontal gyrus of the left orbit were fewer activations during moral disgust processing.Compared with the follicular phase,women had greater activation of the left triangle sub-frontal gyrus when processing pathogen disgust in the luteal phase.However,no brain regions with significant differences in activation during processing of moral aversion in these two phases were identified.In conclusion,these findings suggested that ovarian hormones can have differently effect on pathogen disgust and moral disgust,which was mainly manifested in the enhanced effect of progesterone on disgust processing.The weakening effect of estrogen on disgust processing may be related to the activation of brain regions such as the prefrontal lobe,anterior cingulate gyrus,and the occipital lobe.The results of this study also provided empirical support for the compensatory prophylaxis hypothesis.Future studies should explore the effect of estrogen and progesterone on the processing of disgust caused by different sensory channels,and future studies should also consider their moderating roles in different genders based on strict control of stimulation intensity.Meanwhile,combined with brain imaging technology and animal behavior,using the method of acute administration is an important way to explore the neuroendocrine mechanism of estrogen and progesterone affecting disgust processing.