Mechanism Of Emotion Regulation:Based On Brain Imaging And Neuromodulation Technology

Emotion is closely related to human survival and development.Essentially,effective emotion regulation is necessary for an individual's wellbeing.Therefore,revealing the mechanism of emotion regulation has been a hot topic in the field of cognitive neuroscience.The measures of emotion regulation ability usually include emotion regulation strategy tasks in experimental environments and the use of trait emotion regulation strategies evaluated by psychological scales.Previous studies mainly focused on one or two strategies in experimental tasks to explore the emotion regulation mechanism,but did not comprehensively investigate the functional brain regions related to the emotion regulation process with the use of multiple strategies or combined trait strategies.In this dissertation,the author devised an emotion regulation task paradigm including distraction,cognitive reappraisal and expressive suppression strategy.And the author applied the functional magnetic resonance imaging(f MRI)technology(including task-state and resting-state f MRI)with high spatial resolution,non-invasive transcranial direct current stimulation(t DCS)technology,and the classic emotion regulation questionnaire(ERQ)to study the mechanism of emotion regulation in four separate studies described below:1.The task-based f MRI study of three emotion regulation strategies aimed to explore the specifically activated brain regions of each regulation strategy.Thirtytwo healthy adults were recruited to conduct the emotion regulation f MRI experiment using strategies of distraction,reappraisal and suppression.The results showed that different functional brain regions were involved in the three strategies.Distraction specifically activated most parts of parietal cortex,a small part of the dorsolateral prefrontal cortex(DLPFC)and the insula.Whereas reappraisal evoked activation in most parts of the frontal cortex and temporal gyrus.While suppression triggered activation in the left inferior frontal gyrus(IFG).2.The study of task-based f MRI functional connectivity analysis found that the functional connectivity between key brain regions was different under the three strategies.The strategy effect was used as a behavioral factor,and the insula,amygdala and IFG were regarded as seed regions in the functional connectivity analysis.The results showed that the stronger the connectivity from the right insula to the right IFG,the better the reappraisal effect,and the stronger the connectivity from the left insula to the left IFG,the better the suppression effect.In addition,the stronger the connectivity from the right IFG to the right dorsomedial prefrontal cortex(DMPFC),the better the reappraisal effect.3.The study of resting-state f MRI functional connectivity analysis revealed the relationship between trait emotion regulation strategies and functional connectivity of key brain regions.The ERQ was applied to measure the utilization frequency of trait strategies of one hundred healthy adults,and the resting-state f MRI data were collected.The results showed that in the participants with a medium frequency of reappraisal,the bilateral IFG was the functional hub of reappraisal,and the functional connectivity between the bilateral IFG and other regions was significantly positively related to the utilization frequency of reappraisal.Specifically,the higher the frequency of trait reappraisal,the stronger the connectivity between the left IFG and the bilateral temporal gyrus,superior parietal lobe(SPL),middle cingulate cortex(MCC),left inferior parietal lobe(IPL),and right insula.And the higher the frequency of trait reappraisal,the stronger the connectivity between the right IFG and the bilateral temporal gyrus,DMPFC,and left anterior cingulate cortex(ACC).4.The t DCS study revealed the causal relationship between the IFG and the regulation effect of reappraisal.Forty-two healthy adults were recruited and randomly assigned to the right IFG group(n = 20)and the left IFG group(n = 22).In the two groups,the active and sham anodal t DCS stimulation was applied over the IFG during the emotion regulation task.The results showed that only in the right IFG group(not the left IFG group),compared with the sham stimulation,the active stimulation reduced participants' negative feelings in the use of the reappraisal strategy.That is to say,the anodal t DCS stimulation over the right IFG improved the ability of emotion regulation.To sum up,the present dissertation evaluated individuals' use of emotion regulation strategies from two aspects,the experimental task and psychological questionnaire,and comprehensively revealed the brain mechanism of emotion regulation process from the activation and functional connectivity of key brain regions both in the task-state and resting-state f MRI.It was established that emotion regulation is involved in a wide distribution network of fronto-parietal cortex,temporal gyrus and subcortical region of the insula.Also,the IFG is a core brain region for the use of reappraisal strategy.The key brain regions related to each strategy found in the present study may promote the precise intervention of different individuals in clinical practice.Finally,the intervention study showed that the application of anodal t DCS over the right IFG improves the effectiveness of emotion regulation using reappraisal strategy,which provides a new scientific finding for clinical practice to improve deficits in emotion regulation.