| Mind wandering refers to a drift of attention away from the current task to internal task-unrelated concerns.This phenomenon occurs everywhere and composes nearly 50%of our waking lives.People dissociate from the external environment when their minds wander,which may result in damaged task performance and increasing risk of affective disorders.However,we also glean some functional benefit from mind wandering,such as creative thinking,creative problem solving and avoid pain.Previous studies have shown that brain function is closely related to mind wandering and cognitive activities related to mind wandering.Exploring the cognitive neural mechanisms of mind wandering is important for further understanding of mind wandering and cognitive activities related to mind wandering.In recent years,functional connectivity of resting-state functional magnetic resonance imaging(fMRI)data has become an important indicator for studying the neural mechanisms of mind wandering.Several studies have shown that default mode network(DMN)and frontoparietal control network(FPTC)are the key networks of mind wandering.However,this conclusion is still controversial,and there is a lack of systematic research to explore the stable functional basis of mind wandering.At the same time,the causal relationship between mind wandering and rs-fMRI functional connectivity is an important factor to explore the effective intervention of mind wandering frequency,but the causal relationship between them has not been proved.The relationship between mind wandering and affect is also a problem that researchers have paid more and more attention to in recent years.Previous studies mostly discussed the relationship between mind wandering in the laboratory or the mind wandering characteristics of the subjects and emotions,results show that mind wandering is negatively correlated with positive affect.However,few researcher explored the explored the relationship between mind wandering and emotion in daily life,and explained the relationship from the perspective of brain functional connectivity.The purpose of this study was to find out the stable functional connectivity characteristics of mind wandering and the causal relationship between mind wandering and functional connectivity through longitudinal data,and to explore the relationship between the brain functional connectivity of mind wandering and positive affect through the life experience sampling questionnaire.We carried out longitudinal data collection from 122 participants that underwent three times of MRI scans and simultaneously completed self-reported mind wandering scales over the course of two years to clarify whether a direct relationship existed between brain functional connectivity and mind wandering in study 1.We identified 17 functional connectivity involving the DMN and FPCN that were consistently and stably associated with MW across the three time points.However,only two connections involving the right frontotemporal regions(middle frontal gyrus-supplementary motor area and precentral gyrus-middle temporal gyrus)causally influenced MW frequency in individuals as determined by subsequent cross-lagged analysis.In addition,the results indicated that the mean value of functional connectivity involving the DMN(FC-DMN)in the low mind-wandering(LMW)group was the weakest,followed by mean connectivity in the medium mind-wandering(MMW)group and then the high mind-wandering(HMW)group.These results support previous research linking mind wandering with connections between partial areas involving the DMN and FPCN.Importantly,our findings,indicated,for the first time,that altered brain functional connectivity directly influenced the variation in mind wandering.Study 2 distributed a total of 10 empirical sampling questionnaires to 67 subjects every other day,and collected the rs-fMRI data of the subjects.The purpose of this study was to determine whether the functional basis of mind wandering obtained in the laboratory is related to the frequency of mind wandering in daily life,and focus on the relationship between mind wandering and emotional variables in daily life and to establish a connection with brain function.The results showed that there was a significant positive correlation between the frequency of mind wandering in daily life and positive affect,which is inconsistent with those in the laboratory.The functional connections of middle frontal gyrus-supplementary motor area and precentral gyrus-middle temporal gyrus were not correlated with all behavioral indicators in the experience sampling questionnaire.Mind wandering in daily life has similar functional connection mechanism with positive affect.How pleasant we think things is significantly related to the DMN connection and the DMN/FPTC connection,which has been showed to have relationship with mind wandering in laboratory.This result illustrates the differences between mind wandering in the laboratory and mind wandering in daily life.In general,this study found key functional connectivity of mind wandering:the functional connectivity between DMN and other networks and between FPCN and other networks,and found a causal relationship between mean functional connectivity of middle frontal gyrus-supplementary motor area and precentral gyrus-middle temporal gyrus and mind wandering.It can provide support for the future study of cognitive neuroscience in the field of mind wandering.Moreover,mind wandering in daily life can’t be predicted by functional connectivity in laboratory,and is positively correlated with positive affect.Positive affect in daily life was positively correlated with DMN functional connectivity and DMN/FPCN functional connectivity,which has been associated with mind wandering in previous studies,this result explains the relationship daily life mind wandering and positive affect from the perspective of brain functional connectivity. |
