The Relationship Between MAOA Polymorphism And Feedback-related Negativity In Male Adolescents

Background:People monitor their own behaviors, make the right choices, and regulate their behaviors on the basis of internal and external feedback information, namely decision-making. Appropriate decision-making rely on the effective feedback evaluation process and subsequent adaptive behavior. Many studies used the brain electrophysiological level window into the feedback evaluation processing, such as FRN (feedback-related negativity, which is related to external feedback).Adolescence is the period of existing frequent risky behaviors, adolescents are more prone to all kinds of impulsive and aggressive behaviors. In recent years, some researchers reported those risky behaviors are related to immature or abnormal decision making, furthermore, inappropriate decision making is associated with abnormalities of FRN. Some researchers reported that MAOA polymorphism is related to aggression. However, how do adolescents with different MAOA polymorphism react in the ERPs is unknown.Objective:This research aimed at discussing whether adolescents with different MAOA polymorphism has different FRN.Methods:Based on the previous studies, a total of48subjects were recruited from middle schools of Changsha. Their MAOA genotypes were identified, and there were22MAOA-H subjects and26MAOA-L subjects. We used The Adolescent Health Related Risky Behavior Inventory and Aggression Questionnaire to assess the aggression of the subjects. We chose event-related potential technique to figure out the differences between higher MAOA expression adolescents and lower MAOA expression subjects in amplitude and latency of FRN, during single outcome gambling (SOG) task. All data was dealt with SPSS13.0.Results:Both of the groups have no differences on the aggression scores[F(1,46)=2.14, p>0.05; F(1,46)=3.58,p>0.05]. Compared to MAOA-H subjects, MAOA-L subjects has a more negative FRN amplitude. A mixed-model ANOVA was used to analysis the amplitude of FRN. Main effects for group [F(1,46)=4.794,p>0.05, ηp2=0.118], valence [F(1,46)=55.208, p<0.05,ηp2=0.605] and magnitude [F(1,46)=9.174, p<0.05, ηp2=0.005]were significant. There was no significant interaction. A mixed-model ANOVA was used to analysis the latency of FRN. There was no significant main effect of group[F(1,46)=0.064, p>0.05, ηp2=0.002], valence[F(1,46)=0.049, p>0.05, ηP2=0.001] and magnitude [F(1,46)=4.565, p>0.05, ηp2=0.313].Conclusions:We found that both of the groups have no differences on the aggression level. MAOA-L adolescents showed larger magnitude FRN amplitudes than MAOA-H adolescents, but no difference in the FRN peak latency between the two groups. It is possible that MAOA-L adolescents need more neural activity to achieve similar feedback evaluation process as MAOA-H even though they have the similar processing speed. These results suggest that two group adolescents have the same ability to distinguish external feedback. However, MAOA-L adolescents showed larger magnitude FRN amplitudes than MAOA-H adolescents, but no difference in the FRN peak latency between the two groups. It is possible that adolescents with MAOA-L need more neural activity to achieve similar feedback evaluation process as controls even though they have the similar processing speed. This study suggests the FRN may be used as a neuro-physiological marker of aggression.