The Effects Of The Natural Scene Picture Viewing On Stress Recovery And Neural Correlates

BackgroundWith the urbanization and increasing social pressure in modern life,mood and anxiety disorders are more common among urban residents.Recovery of urban residents under stress is affected and the rate of people born or raised in the city suffering from mood disorders has increased greatly.The restoration benefits of the natural environment have always been valued not only for reducing anxiety,negative emotions,and maintaining positive emotions,but also for improving people’s cognitive function and mental health.While visiting a natural scene has higher requirements for natural scene facilities and people’s time.In this context,it is necessary and important to explore whether only viewing pictures of natural scenes can restore the state after stress,as well as visiting natural scenes personally.If viewing pictures of natural scenes is also beneficial to recovery after stress,the brain mechanism behind its recovery effect can be further explored.Besides,viewing pictures of natural scenes can be used as one of the ways to promote recovery after stress to provide positive coping approaches for the recovery and maintenance of mental health in urban settings.PurposesThis study aims to induce individuals’ stress and negative emotions through the Trier Social Stress Test(TSST).By comparing the viewing of natural scene pictures and the viewing of urban pictures,to explore the effect of natural scene picture viewing on the recovery of emotions,stress,and stress-reactive rumination after TSST.On the basis of behavioral experiments,we use the functional magnetic resonance imaging,and the analysis method of static functional connectivity and dynamic functional connectivity to further explore the neural correlates of natural scene picture viewing and its dynamic recovery effects over time.MethodsStudy 1:Using the convenience sampling method,128 healthy college students were randomly divided into a natural scene picture viewing group and an urban scene picture viewing group.The Trier social stress test was used to induce stress in the two groups.After that,the participants in the natural group and the urban group watched the natural scene pictures and the urban scene pictures respectively.Collecting subjective scores on mood,stress,and stress-responsive rumination after viewing the pictures.Study 2:On the basis of Study 1,49 participants were invited to participate in the fMRI scanning experiment.All participants were randomly divided into a natural scene picture viewing group and an urban scene picture viewing group after the Trier social stress test.Subjective scores on mood,stress,and stress-responsive rumination were collected after TSST and picture viewing.ResultsStudy 1:The positive emotion,negative emotion,degree of tension,degree of relaxation and stress-reactive rumination between the NG group and the CG group were significantly different in the ratio R1 after stress(ps<0.001).It means that the stress was induced successfully.And there was no significant difference(ps>0.05)between the two groups in the ratio R1 of the above items.After picture viewing,the natural group had higher recovery of positive emotion(t(126)=3.24,p=0.002,Cohen’s d=0.58)and negative emotion(t(126)=-3.42,p=0.001,Cohen’s d=-0.61)than the urban group.Study 2:First,in terms of overall recovery after stress,significant differences in static functional connectivity between the right amygdala and left pars opercularis(t=3.62,voxel level p<0.005,cluster level p<0.05),left middle frontal gyrus(t=3.79,voxel level p<0.005,cluster level p<0.05)were observed.Then,from segmental recovery effect of picture viewing,there was a significant difference in the dynamic functional connectivity between the left amygdala and left middle frontal gyrus during the prophase of picture viewing(t=3.96,voxel level p<0.005,cluster level p<0.05)in the NG group,and a significant correlation was observed with R2 of the level of relaxation between the two brain regions in the NG group(r=-0.55,p=0.004);During the metaphase of picture viewing,there were significant differences in static functional connectivity between the left amygdala and left middle temporal gyrus(t=-3.68,voxel level p<0.005,cluster level p<0.05)between the two groups.There were significant differences in the dynamic functional connectivity between the right amygdala and the right middle frontal gyrus(t=-3.90,voxel level p<0.005,cluster level p<0.05)in the NG group,and a significant correlation(r=-0.44,p=0.02)was observed with the recovery ratio R2 of the degree of relaxation.ConclusionsIn the prophase of picture viewing,the relationship between higher dynamic functional connectivity and faster recovery of tension was observed in the NG group,which may mean that natural pictures gradually promote the regulation of the left middle frontal gyrus to the left amygdala in the prophase of picture viewing.Although no significant changes were observed in static functional connectivity,a trend towards underlying connectivity has been demonstrated through enhanced dynamic functional connectivity.In the metaphase of the picture viewing period,the dynamic functional connectivity between the right amygdala and the right middle frontal gyrus gradually decreased.The decrease in dynamic functional connectivity may mean that the functional connectivity between the middle frontal gyrus and the amygdala has shown stability after the previous adjustment,that is,the variability of connectivity is reduced.The better the stability,the stronger the recovery of tension.It can be seen that natural picture viewing promotes the role of the left and right amygdala in emotion regulation,and the top-down regulatory mechanism of the middle frontal gyrus has been promoted in the prophase and metaphase of picture viewing.