The Neural Mechanism Of Working Memory Impacting Emotion Regulation And Its Intervention

Living in an era of rapid change,where stress,anxiety and depression,etc.always follow us.Emotion is induced by the events or stimuli,which has a significant influence on subjective experience,behavior and neural response.Facing emotional events with a more adaptive manner is significant for the individual,directly impacting our well-being and social function.The progress of enhancing adaptive emotional response is usually known as emotion regulation(ER).Working memory(WM),a limited system maintains and processes information in the short term,is related to attentional control.And WM is the basis of complex cognitive process in human beings.Importantly,the process of emotion regulation depends on WM,such as selectively maintaining goal-related information,suppressing the interference of affective distractions,updating the meaning of negative situations,and reappraising negative stimuli.But so far,only a few of behavioral studies have examined the relationship between them.Little is known about the cognitive and neural mechanisms of WM that affects emotion regulation.It is important for understanding the interaction between WM and emotion to know how WM affects ER,what is the cognitive and neural mechanisms behind this effect,and what changes will happen to ER after intervention for WM.To this end,we conducted four studies,a total of nine experiments,from the influence mechanism to the intervention to systematically explore the psychological mechanism and basic neural mechanism of WM impacting ER.In study 1,we explored the relationship between the individual difference in WM and ER from the behavioral level;and we investigated the advantage of ER in the individual with high WM from the neural level by using functional magnetic resonance imaging(f MRI).Besides,study 2 was used to explore the influence of the expectations about the training gains on ER,which provides a new perspective for the experimental design of intervention.In study 3 and 4,we further examined the impact of interventions on ER through WM training and neurofeedback training based on the hub area of WM,respectively.In study 1,we first investigated the relationship between WM and ER in the experiment 1.Participants were required to perform two tasks.The first task was the adaptive dual n-back task where visual items were presented sequentially.Simultaneously,auditory items were presented sequentially though headphone.Participants made a response(“A” key for visual target;“L” key for auditory target)when the current stimuli matched the one presented n positions back in the sequence.In the n-back task,the difficulty of n-back would vary with the level of n.The other task was ER task where a cue(look neutral picture,look negative picture and reappraise negative picture)was followed by an emotional stimulus.Participants viewed these stimuli depending on the requirements of the cue.Then,they rated their negative emotional experience at this moment.The results showed that WM performance was positively correlated with ER effect(Negative-Regulate).That is,the better WM perfoemance you have,the more effectively you can regulate your negative emotion by using cognitive reappraisal strategy.In experiment 2,we grouped individuals with their WM performance,and explored their difference in emotional processing(stimuli match task)using f MRI.We found that,compared to individuals with low WM,individuals with high WM had lower response time in stimuli match task;they had an ascending trend on accuracy.We conducted psychophysiological interaction(PPI)analysis to find out the change of functional connectivity caused by the regulatory advantage,found that individuals with high WM induced enhanced functional connectivity between amygdala and the emotion regulation network(ERN).And the mean strength of those connectivity was positively related to behavioral regulatory advantage.These evidences suggested that WM could influence ER in which individuals with high WM displayed a regulatory advantage.The functional coupling between amygdala and ERN was the neural basis of this regulatory advantage.In study 2,the impacting of expectations on ER was explored by simulating the experimental design of WM training.The experiment involved three stages: pre-test,expectation-forming stage and post-test.Participants were instructed to complete an ER task in pre-test after they arrived at the laboratory;then,they were randomly assigned to the expectation group and the control group.In the expectation-forming stage,expectation group had five minutes to read a leaflet that contained suggestive words such as “brain training”,“cognitive enhancement”;while the control group rested for five minutes.Then,they needed to complete a pseudotraining.All participants performed the same training,in which the duration of training was 1 day(experiment 3)or 7 days(experiment 4).It was worth note that this training procedure would not produce real training effect as the task used in this study required fewer demands for WM.After that,a similar ER task was employed in the post-test.The results demonstrated that,compared with the control group,the expectation group showed less negative emotion from pretest to posttest in the context of WM training(simulating the training task and training duration).These results express the view that it is important to match the expectations between the training and the control groups in the real WM training,which directly influence the reliability of experimental findings.In study 3,cognitive WM training was used to test the regulatory advantage of WM-related individual difference and its neural basis.At first,we matched the expectations caused by task difference between training task and control task,suggested that visual search task had comparable expectation about improving ER ability with WM task and could serve as the training task of the control group.Then,other individuals were recruited publicly through forums,We Chat public account,QQ group to participate in the WM training.Any suggestive words would not be displayed in the recruitment advertisement.The experiment contained pre-test,training stage and post-test.The training stage comprised of 7 days(short-term)or 15 days(long-term)training with a daily training time of 30 minutes.The adaptive dual n-back task served as the training task of the training group;the task of the active control group was the visual search task that required fewer demands for WM.ER task was measured in pre-test and post-test.We concluded that participants following short-term training on WM showed slight improvement on emotional experience from pre-test to post-test(experiment 5);but this improvement was significant after long-term training(experiment 6).Importantly,the combined analysis of experiments 5 and 6 implied that the more training you paid,the less negative emotion you got.These results suggested a dose effect on training effect.In order to test the neural basis of training-related improvement on ER,experiment 7 recorded the resting-state f MRI data in pre-test and post-test,respectively,which based on experiment 6.In the training group,we found an increased functional coupling between amygdala and ERN from pre-test to post-test.These findings suggested that individuals who received WM training might regulate their emotion in an automatic manner to increase the adaptive emotional response.And the functional connection between amygdala and ERN was the neural basis of this transfer effect.In study 4,the neurofeedback training based on the core brain region of WM was used to investigate the regulatory advantage of WM-related individual difference and its neural basis.In experiment 8,participants chose four days among two weeks to complete neurofeedback training with a daily training time of ～20 minutes in the laboratory.During the training,the feedback group learnt to self-regulate the activation of their right dorsolateral prefrontal cortex(r DLPFC)according to the feedback signals;while the feedback signals received by the control group came from the other people instead of themselves.ER task was recorded in pre-test and post-test,respectively.The improving regulatory effect was found in the feedback group than in the control group when they used cognitive reappraisal strategy.Based on experiment 8,the resting-state f MRI data were obtained in both pre-test and post-test(experiment 9).We found that neurofeedback training increased the functional coupling between amygdala and ERN.Thus,we provided more evidence about the regulatory advantage of WM-related individual difference in intervention level,in which the functional coupling between amygdala and ERN might be responsible for this regulatory advantage.Overall,based on the above results,the most noteworthy contribution of the current study is the finding for the first time that individual difference in WM can induce an advantage of emotion regulation.Combining two different research fields,we found the impact of WM on ER from influence mechanism and intervention.Furthermore,we revealed the neural basis of this regulatory advantage from the level of brain science,and indicated that WM-related regulatory advantage was decided by the functional coupling between amygdala and ERN.These findings have important theoretical significance and practical value,and can deepen our understanding of theoretical and disease models related to WM and ER,and provides an essential reference for future intervention research.