Neural Synchronization Of Different Types Of Emotional Memory Transmission

Memory transmission refers to the process of the speaker's sharing past experiences or skills with the listener,involving three steps: the speaker's encoding and retrieval,the linguistic communication from speaker to listener,and the listener's mental construction of the events.Studies have shown that the processing depth of different emotional information is significantly different.Compared with neutral information,emotionally related information is processed more deeply.When recalling past experiences,positive emotional events were easier to recall and more accurate.However,there were few studies on whether there was a significant difference in the memory transmission of different emotional information.In addition,most previous research on the neuro mechanism of memory transmission only focused on single brain activity of the speaker or listener,ignoring brain-brain interaction during this process.Therefore,present study used EEG-based hyperscanning technique to discuss problems above,trying to provide scientific evidence from the perspective of human interaction.In this study,subjects were divided into two groups to do memory transmission tasks of neutral information and positive(or negative)emotional information.In the task,the speaker told the story of the movie clip and expressed her current emotion.This expression was made into a recording(about 7 minutes in length).Subsequently,the listener listened to a neutral and an emotional(positive or negative)information recording,and then evaluated the emotional state and told the story he or she listened.The effect of memory transmission is measured by the ratio between the listener and the speaker 's retelling score(defined as “recalling rate”).The ratio of the absolute value of the difference between the speaker's and the listener's emotional intensity and the speaker 's emotional strength(defined as “emotion rate”)was used to measure the effect of emotion transmission.During the speakers narration and the listeners listening to the recording,the subjects brain activities were recorded separately.The phase locking value(PLV)analysis was used to calculate the interpersonal neural synchronization(INS)between the speaker and the listener,which was to measure the interaction between two brains during memory transmission.In addition,in order to explore the role of empathy traits in this process,a questionnaire survey was used to measure the empathy traits before the experiment.Firstly,the recalling rate and emotion rate were analyzed,and results showed that(i)the recalling rate of emotional information was significantly higher than that of neutral information.Compared with negative emotional information,the recalling rate of positive emotional information was higher,and that(ii)the score of perspective taking was negatively correlated with the emotion rate of positive emotional memory,and the score of personal distress was negatively correlated with the emotion rate of negative emotional memory.Secondly,the analysis of the phase locked value(PLV)between different groups found that:(i)Compared with the transmission of neutral memory,the positive emotional memory transmission induced higher INS in the occipital lobe in alpha frequency band,parietal-occipital part and parietal lobe in delta frequency band.Furthermore,there was a marginal significant negative correlation between the INS in the alpha band of the occipital lobe and the recalling rate of positive emotion information.(ii)Compared with neutral information,negative emotional memory transmission was accompanied with lower INS in the parietal lobe-prefrontal lobe in beta band,as well as the occipital lobe,occipital-temporal,temporal-parietal,and prefrontal-parietal in theta frequency band.The INS of theta band in the temporal-top position is negatively correlated with the recalling rate of negative emotion memory.(iii)Compared with negative emotion memory,higher INS in gamma band occurred in the occipital-temporal,occipital-frontal,frontal-temporal,and temporal lobe regions,as well as higher INS in theta frequency occurred in the occipital lobe,temporal-parietal,frontal-temporal and parietal-prefrontal regions.Furthermore,the INS of the frontaltemporal part in theta band showed a significant positive correlation with the recalling rate of emotional memory,and the theta band INS of the frontal-temporal had a marginal significant positive correlation with the recalling rate of the negative emotional memory.To sum up,present study found that the memory transmission of emotional information was better than that of neutral information,while the memory transmission of positive emotion information was better than that of negative emotion information.The different dimensions of empathy traits play roles in the memory transmission of different emotional information.The memory transmission of different emotional information was related to the interpersonal neural synchronization in multiple parts of the brain.Therefore,this study firstly attempts to use hyperscanning technique to explore the influence of emotional information on memory transmission in a level of interactive brains,which provides new scientific evidence for further elaborating the brain mechanism of emotional memory transmission.