Imaging Studies Of Aggressive Behavior

Aggressive behavior is a kind of behavior that causes physical or psychological harm to others using physical actions,speech,etc.with the purpose of punishing or infringing others.Aggressive behavior can affect the occurrence and performance of various mental diseases.Various violent incidents in society are inseparable from aggressive behavior,which pose a major threat to the safety of the personal and property of each member of society.The occurrence of aggressive behavior is closely related to genetic and environmental factors.Imaging studies have shown that the occurrence of aggressive behavior may involve the interaction of multiple neural circuits.Among them,the neural circuits that support emotional response and arousal,emotional regulation,and cognitive control are all related to the occurrence of aggressive behavior,but how the neural circuits interacts to affect the individual's aggressive behavior remains unclear.Therefore,from the perspective of imaging genetics,this article aims to explore the neural mechanism of aggressive behavior,and how the candidate genes and environment affect the functional connection mode of the brain and aggressive behavior with resting magnetic resonance imaging data of healthy subjects.First,imaging studies of aggression have shown that the occurrence of aggressive behavior is related to multiple functional networks of emotional regulation and cognitive control,and COMT Val158 Met is also closely related to the occurrence of aggressive behavior,so COMT Val158 Met may affect individual's aggressive behavior through impacting the functional connectivity between emotion-regulation network and the cognitive-control network.In this study,we first selected multiple brain regions of the central-executive network(CEN)involving in executive control and the emotion-regulation network(ERN)involving in emotion regulation as regions of interest.Resting functional imaging data was used to calculate the functional connectivity between these brain regions and explore the relationship between these connections and aggressive behavior;then COMT Val158 Met was selected as a candidate SNP to study the impact of this polymorphism on the functional network related to aggression.The results showed that the functional connectivity between right frontal gyrus(MFG)of CEN and left precentral gyrus(Pre CG)was significantly associated with aggressive behavior(p <0.001,Bonferroni correction).ANOVA analysis showed that COMT Val158 Met and gender had a significant interaction on the scores of aggressive thinking,and the interaction on the rs FC of MFG-Pre CG was borderline significant.Therefore,the results of this study indicate that aggressive behavior may be an impulsive behavior of emotional dysfunction.Insufficient control of the central-control network may lead to a decline in emotional processing ability,and thus improve the level of attack.In addition,this study also suggests that COMT Val158 Met may affect the individual's aggressive behavior by affecting the functional connectivity of the brain network of the emotional-regulation network and the central-executive network.In the second study,in addition to the genetic influence,childhood trauma as an early life stress event is an important environmental factor for aggressive behavior.Childhood trauma(CT)has been associated with altered sensitization of the hypothalamic-pituitary-adrenal(HPA)axis,which is linked to hippocampal neuroplasticity.Catechol-O-methyltransferase(COMT)is widely expressed in the hippocampus(HIP)and is implicated in pain and stress responsivity.Hence,either exposure to CT or genetic variations may affect hippocampal morphology and function.Altered hippocampal volume and activity have also been shown to be correlated with aggression.Using resting state functional MRI and behavioral questionnaires,this study examined whether both CT and haplotypes of COMT moderate hippocampal function and thus affect human aggressive behavior.Three major haplotypes were generated from thirteen single nucleotide polymorphisms(SNPs)within the COMT gene and formed three haplotypes corresponding to high,medium,and low enzymatic activity of COMT.The results showed interactive relationships between COMT and the Childhood Trauma Questionnaire(CTQ)on the functional connectivity(FC)of the bilateral HIP-orbital frontal cortex(OFC).Specifically,CT experience predicted lower negative HIP-OFC coupling in the APS and HPS haplotypes,whereas CT experience predicted greater FC in the LPS haplotypes.We also observed a conditional mediation effect of the right HIP-OFC coupling in the link between COMT and aggressive behavior,which was moderated by CT experience.These results suggest that COMT and CT have a combined effect on aggressive behavior through hippocampal function.This mediation analysis sheds light on the influence of childhood experience on aggressive behavior in different genetic backgrounds.In conclusion,from the perspective of imaging genetics,this study is based on functional circuits related to aggressive behavior,from a SNP of COMT gene to haplotype,from the independent influence of genetic factors to genetic and environmental interactions.Research have shown that the occurrence of aggressive behavior is affected by genetic and environmental interactions and is related to abnormal information transmission between emotional networks and cognitive control networks.This study provides new evidence for us to clarify the neural mechanism behind the aggressive behavior,and it is also important for understanding the causes of the aggressive behavior.