EMMN Reflects Enhenced Response To Deviant

Automatic detection of facial emotion is very important for individual survival.Many studies using event-related potentials(ERP)technology show that emotion-related mismatch negativity(EMMN)indexes automatic facial emotion processing.In the existing studies,few studies have explored the influence of experimental variables such as visual refractoriness and low-level physical properties on the EMMN effect,and the results are controversial.Two studies were carried out to explore the differences in the EMMN effect under different experimental conditions:In the first study,meta-analysis was used to systematically review the research on automatic facial emotion processing using EMMN as an indicator.After literature searching and screening,35 studies(721 subjects)were identified.The results showed that:(1)significant EMMN effects were found in both early(0 ～ 200ms)and late(200 ～ 400ms),and the occasional emotional face induced more negative ERP in two-time windows,indicating that EMMN reflected the probability of early and late ERP components related to facial emotion(2)the types of deviant-standard stimulus pair affect the early EMMN effect but not the late EMMN effect: in the early interval,different deviant-standard stimulus pair induced larger EMMN,indicating that the difference of low-level physical properties increased the early EMMN effect;(3)in the study of the same deviant-standard stimulus pair,the equal probability and nonequal probability EMMN effects were not significant in the two-time windows(4)both early and late EMMN had a negative bias,that is,EMMN induced by negative emotion was significantly larger than that induced by positive emotion.These results indicate that the EMMN effect is influenced by the deviant-standard stimulus pair type and emotion type.Through the systematic review of EMMN,we found that there is no study to explore whether the EMMN effect is affected by probability under the condition of the same deviant-standard stimulus pair.That is to say,after excluding the influence of low-level physical information,it is not known whether visual refractoriness affects the EMMN effect.The question is whether the EMMN effect is a reduction in the neural activity produced by repeated stimuli or an increase in the activity of oddball stimuli.In the second study,an ERP experiment was used to explore this problem.Specifically,in the experiment,subjects were presented with oddball sequence,reverse oddball sequence,and equiprobable sequence,and the differences in amplitude,source location,and time-frequency decomposition among oddball EMMN(EMMN 1),reverse oddball EMMN(EMMN 2)and equiprobable EMMN(EMMN 3)were analyzed.The difference between EMMN2 and EMMN3 is caused by the difference in the probability of emotional face repetition.The results showed that EMMN1,EMMN2,and EMMN3 were significant in 100 ～ 350 ms,but there was no significant difference among them;In addition,the time-frequency analysis results also showed that EMORs1,EMORs2,and EMORs3 were significant in theta band in 100 ～ 300 ms,but there was no difference among them.The results showed that low level of physical information and visual refractoriness did not affect EMMN or EMORs,indicating that mismatch effect was the enhancement of neural activity to new stimuli rather than the weakening of neural activity caused by repeated stimuli,supporting the memory-trace explanation of EMMN effect rather than the sensory fatigue explanation or the visual refractory explanation.In addition,the analysis of EMMN and EMORs emotion types shows that EMMN has a negative bias.Compared with neutral emotion,the EMMN effect of negative emotion has a larger time range and hemispheric range;within 100 ～ 200 ms,EMORs of negative emotion is significantly positive,but neutral is not significant,which has nothing to do with the frequency band,indicating that negative emotion induces greater mismatch neural oscillations.In conclusion,through the meta-analysis of previous EMMN research results,this study found that the deviant-standard stimulus pair type and emotion type affect the EMMN effect,but in the case of the same deviant-standard stimulus pair,the probability difference does not affect the EMMN effect.The results of the meta-analysis also show that EMMN has a negative bias.On this basis,through ERP Experimental study,it is found that a low level of physical information and visual refractoriness do not affect the EMMN effect.The analysis of emotional effect shows that both EMMN and EMORs have a negative bias,and the conclusion is consistent with the evidence in Study 1.