Stress-related Brain Function In Individuals With High And Low Rumination

Objective:Rumination is associated with the development and maintenance of various psychiatric disorders.Stress is an important etiological mechanism of these disorders.Previous studies have shown that individuals with high rumination are more vulnerable to stress,and the stress sensitivity increases the likelihood of developing disorders.However,the effects of high and low levels of rumination on neurophysiological changes during stress remain unclear.Therefore,this study intends to provide empirical evidence for the role of rumination in stress sensitivity and disease prevention by examining and comparing the stress-related brain function characteristics of individuals with high and low rumination.Methods:A total of 112 healthy adult participants were included in this study,of which 55 subjects had high rumination and 57 subjects had low rumination.Using the Montreal Image Stress Task(MIST),all subjects completed task-state f MRI scans,and completed subjective stress assessment and salivary cortisol sample collection during the task.This study compared the differences in subjective stress response,cortisol response,stress-related brain activation,and functional connectivity between the high and low ruminative groups,and explored the role of rumination and gender in stress-related interactions.Results:high ruminators exhibited greater cortisol responses when compared to low ruminators during the MIST(p<0.001).The results of imaging data analysis also showed higher activation of the right middle frontal cortical(MFC＿R)under stress in high ruminative group(p<0.05,FWE correction).The results of PPI with the MFC＿R as the seed point showed that there was no significant difference of two groups in functional connectivity.The results of correlation analysis showed that rumination was positively correlated with activation of the MFC＿R,cortisol area under the curve with respect to increase(AUC_I),depression and trait anxiety(p<0.05).The activation of the MFC＿R was positively associated with depression and anxiety(p<0.05).Further exploration of the mediating effects of rumination on activation of the MFC＿R and depression or anxiety respectively,found that rumination had a mediating effect between activation of the MFC＿R and depression(β=0.273,p=0.003).The results of MANOVA showed that there was a significant interaction between rumination and gender in activation of MFC＿R:the activation of the MFC＿R in the high ruminative female group was significantly higher than that in low ruminative female group(p<0.05),while there was no significant difference between the high and low male groups(p>0.05);there was a marginally significant difference in the activation of MFC＿R between women and men in the high ruminative group(p=0.052),while there was no significant gender difference in the low ruminative group(p>0.05).Conclusion:There are differences in the response characteristics of individuals with high and low rumination in psychosocial stress tasks,individuals with high rumination have more increased cortisol levels and stronger activation of the MFC＿R under stress,suggesting that stronger activation of the MFC＿R may be the neural mechanism by which promote stress sensitivity.The difference in brain function between individuals with high and low rumination under stress is significantly gender-specific,suggesting that it may be the underlying neural mechanism that female individuals with high rumination are more vulnerable to depression.