Sex-related Brain Networks Of Emotion Regulation

Emotion regulation (ER) refers to the affective and cognitive processes by which the individual influence emotional perception, appraisal and response. An individual’s capacity for emotional regulation may relate to both healthy and pathological variations in general well-being and social behaviour. Numerous studies have demonstrated sex-related differencesin emotional perception, experience, response, and regulation. In particular, sex-related differences in emotional regulation could be an important factor for the divergence in vulnerability in neuropsychiatric disorders between men and women. However, the neural basis of sex differences in ER remains poorly understood. Previous studies have suggested that there are at least two separable pathways linking prefrontal cortical activities with reductions in negative emotion during reappraisal:one through the nucleus accumbens/ventral striatum (NAcc/VS), which may generate positive appraisals, and one through amygdala and insula, which may generate or enhance negative appraisals. Therefore, the current thesis mainly investigated the neural basis of sex differences in ER based on its connectivity patterns of the amygdala, insula and NAcc, respectively.The four major innovative works of this thesis are as follow:1. The first study examined the neural basis of sex-related differences in ER on the basis of amygdaloidal subregion and found that the sex-specific functional connectivity changes associated with ERlevel were only seeded in the centromedial amygdala (CM). Women with a higher ER score had stronger resting state functional connectivity (rsFC) between the right CM and the anterior insula (AI) and the superior temporal gyrus (STG). But the association between a higher ER score with stronger rsFC for men was identified between the right CM and the mdial superior frontal gyrus (mSFG)..2. The second study aimed to test sex-related alterations in the intrinsic functional connectivity of the insula subregions. We found that the sex-specific functional connectivity patterns associated with ER were only seeded in the dorsal anterior insula (dAI). Specifically, women with a higher ER score had a stronger rsFC between the right dAI and the ventromedial orbital frontal cortex (vmOFC), whereasmen with a higher ER score had a weaker rsFC between the left dAI and the lateral orbital frontal cortex (lOFC).3. The third study, using brainnetome atlas, investigated sex-related alterations in the intrinsic functional connectivity between the left and right NAcc and the other 244 brain areas. We found that men with a higher ER scores had a stronger rsFC between the right NAcc and the posterior cingulate cortex (PCC), whereas women with a higher ER scores was associated with stronger rsFC between the right NAcc and the posterior middle temporal gyrus(pMTG) and dorsal anterior insula(dAI), and also between the left NAcc and the right inferior frontal gyrus(IFG) and dAI..4. Finally, the laststudy in current thesis aimed to examine sex-related difference in the behavioral studies. The results showed that men with a higher ER score were more quickly in recognizing emotiortal face, and more efficient in positive emotion regulation than women. In addition, the men with a higher ER score reported higher reappraisal scores than the men with a lower ER score. However, the women with a higher ER score took long time in recognizing emotional face, more efficient in negative emotion regulation than men and reported lower expressive inhibition scores than the women with a lower ER score.Inconclusion, using rsFC methods our studies established the relationship of the ER ability and sex-related neural circuits and verified on the behavior of sex difference in the emotional processing and regulation.the three rsFC studies found the sex-specific functional connectivity patterns associated with ER were seeded in the CM, dAI and NAcc. For the two pathways of reducing negative appraisal and enhancing positive appraisal in ER, the CM and NAcc were modulated via the top-down description-based appraisal system (mSFG, PCC) in men, whereas in women, the modulation of ER was achieved by the bottom-up perceptual appraisal system (STG, pMTG)and affective appraisal (AI) system. The dAI was modulated via the different top-down outcome-based appraisal system in men(IOFC) and women(vmOFC). These results suggested that men’s ER ability was associated with top-down processing and women’s ER ability was associated with both top-down and bottom-up processing, that may explain why men with a higher ER score were more efficient during emotional processing.Our findings will provide a better understanding of the mechanisms underlying sex difference with regard to ER ability and facilitate future studies in these areas of sex-related difference in psychiatry with emotion dysregulation.