| Sleep plays a critical role in physical health and mental health across the lifespan.Sleep deprivation is common in life,and its a common symptom and risk factor for a range of psychological disorders and psychopathology.In general,sleep deprivation increases the experience of negative emotions,reduces the production of positive emotions and alters the way individuals understand,express and modify their emotions.Because difficulties with emotion regulation are a prominent feature of psychological disorders and psychopathology,a growing body of research is looking at emotion regulation as an explanatory mechanism for the risk of sleep deprivation induced psychological disorders.Laboratories often use the sleep deprivation experimental paradigm to explore the effects of sleep deprivation on individuals’ cognitive and emotional processes.Emotion regulation and its functions are widely referenced in sleep deprivation-related research,but studies that directly explore the effects of sleep deprivation on emotion regulation using empirical studies remain limited.The results of resting-state EEG studies that have shown that 24-hour sleep deprivation impairs the function of individuals’ emotion regulation brain networks.However,this result has not been further validated by brain imaging studies.And the results of current task-state studies on the effects of 24-hour sleep deprivation on emotion regulation are inconsistent.In order to provide further evidence on the effects of sleep deprivation on emotion regulation,this study was conducted using resting-state functional magnetic resonance imaging(f MRI)and task-state f MRI,respectively.The aim of Study 1 was to investigate whether 24-hour total sleep deprivation(TSD)impairs dynamic brain network connectivity for emotion regulation.The hypotheses:(1)d FNC would predict individual emotion regulation under nocturnal sleep(NS)condition;and(2)TSD would impair normal state dynamic brain network connectivity for emotion regulation.In this study,resting-state f MRI was used to explore the effects of 24-hour TSD on emotionregulated brain networks.In order to better control the possible effects of inter-subject variability on the experimental results,a within-subjects experimental design was used to collect 8-minute resting-state f MRI data under NS and TSD conditions,respectively.Furthermore,the sliding time window method was used to analyse the effect of sleep deprivation on individual dynamic functional brain network connectivity(d FNC).Meanwhile,the functional brain network connectivity status under NS condition was correlated with the scores of the questionnaire related to emotion regulation.If significantly correlated,regression analysis was used for prediction to identify the dynamic brain networks associated with emotion regulation.And,we further explored whether abnormalities in dynamic brain networks related to emotion regulation occur after TSD.The aim of Study 2 was to investigate whether there were differences in the subjects’ performance on the emotion regulation behavioural tasks and their brain effective connectivity in the TSD and NS conditions.The hypotheses were that(1)behavioural performance would decrease after TSD and(2)the strength of the effective connections between prefrontal brain regions or prefrontal-amygdala brain regions would decrease during emotion regulation after TSD.In this study,task-state f MRI was used to explore the effects of 24-hour TSD on the executive phase of emotion regulation.Considering that reappraisal and distraction are the most studied and adaptive emotion regulation strategies,this study explored the effects of sleep deprivation on the execution of reappraisal(reinterpretation strategy)and distaction.A 2(TSD,NS)× 2(reappraisal,distraction)within-subject experimental design was used to collect taskstate f MRI data in the TSD and NS conditions,respectively.Also,subjective completion scores,distracted numerical test error rates,and emotion regulation success rates were used as measures of the emotion regulation behavioural task.For the analysis of f MRI data,dynamic causal modelling(DCM)was used to analyse whether there were differences in effective connectivity(i.e.,the effect of one brain region on the other)between prefrontal brain regions or between prefrontal-amygdala brain regions during subjects’ performance of the emotion regulation task under the two sleep conditions.The results of Study 1 found that after TSD,a brain state showing anti-correlation of the DMN with other networks(state 1)had a significantly lower mean dwell time and fraction of state;a brain state showing strong connectivity within task-related subnetworks and negative correlation of cortico-subcortical networks(state 2)had a significantly higher mean dwell time and fraction of state;and a brain state showing extensive "hyperconnectivity"(state 3)showed a significant increase in mean dwell time and fraction of state.The above results are similar to those of previous studies examining changes in individual d FNC brain states after TSD,suggesting that the d FNC matrix of brain states effectively reflects the time-varying abnormalities in functional network connectivity after 24 h TSD.Meanwhile,the findings revealed that fraction time of state 2 was significantly predicted the acceptance,the adaptive emotion regulation strategies,and the self-blame of the Cognitive Emotion Regulation Questionnaire(CERQ)in the NS condition.In the TSD condition,the state was somewhat disrupted,as evidenced by increased negative correlations in the corticalsubcortical network,and a tendency of hyperconnectivity within the task-related subnetwork.And,there was no state correlates with the emotion regulation related questionnaire under TSD condition.These results suggest that the d FNC in the NS condition predicts individual emotion regulation and that TSD impairs the dynamic brain network connectivity of emotion regulation.The results of Study 2 found that,subjective completion scores and emotion regulation success rates on both reappraisal and distraction were significantly reduced after TSD,and there was no interaction effect.Moreover,after TSD,subjects showed higher error rates on numerical tests following distraction conditioning.The DCM results indicated that,the strength of the left ventral lateral prefrontal cortex(VLPFC)to left dorsal lateral prefrontal cortex(DLPFC)effective connection was diminished during reappraisal conditioning,and the strength of the right DLPFC to right orbitalfrontal cortex(OFC)effective connection was reduced during distraction conditioning after TSD.In summary,the present study concludes that(1)24-hour sleep deprivation impairs the time-varying connectivity of the individual’s functional brain network for emotion regulation,and that this dynamic brain network for emotion regulation exhibits abnormal connectivity patterns under TSD condition;(2)It was also found that 24-hour sleep deprivation generally impairs individuals’ executive performance in emotion regulation and is not specific to regulation strategies.Moreover,the neural representation of this decrease in behavioural performance is a reduction in the strength of effective connectivities between prefrontal cognitive control brain regions during emotion regulation.Overall,the present study investigated the effects of sleep deprivation on dynamic neural mechanisms of emotion regulation using resting-state f MRI and task-state f MRI,which may fill the current research gap to some extent and provide further evidence for controversial findings.Furthermore,by investigating the brain imaging mechanisms of sleep deprivation on emotion regulation,it can provide some value for the treatment of clinical psychiatric disorders and mood disorders.In addition,by revealing the effects of sleep deprivation on the neural mechanisms of emotion regulation,it can help individuals to improve their awareness of sleep health and emotional health,and promote them to maintain healthy sleep and develop good emotion regulation,thus enhancing their sense of well-being in life. |
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