Brain Basis Of Proactive Aggression

Aggression is a behavioral reaction or tendency that causes physical or psychological harm to another individual who intends to avoid the harm.Aggressive behavior can pose a threat to individual health,human collaboration,social economy,and safety.Therefore,the research of aggression has been concerned.Aggression is a heterogeneous concept.A widely accepted classification is proactive and reactive aggression,based on motivation.Reactive aggression,which is also caled as impulsive aggression,is behavioral reaction or tendency that is triggered by provocation and/or perceived threat,whereas proactive aggression,which is also cal ed as premeditated/instrumental/ predatory /cool aggression,is behavioral reaction or tendency that refers to obtaining personal goals or gains through aggressive means with prior deliberation and moral disengagement and can occur without provocation and with a lowlevel of emotional arousal.Terrorist attacks,theft,robbery,premeditated crimes,campus bullying,rumors and slanders and so on are the manifestations of proactive aggression.Proactive and reactive aggression differ in their psychological,physiological,and biological manifestations as well as in etiology.Therefore,the research of proactive aggression has important scientific value and practical significance.According to the stability across time and situation,proactive aggression can be divided into two categories including state proactive aggression and trait proactive aggression.While state proactive aggression is aggressive response triggered by a specific condition and changes with time and scenario.It is often measured by laboratory tasks.Trait proactive aggression refers to disposition that individuals tend to conduct proactive aggressive behavior in daily life across times and situations or behavior patter.It is a personality trait and often measured by questionnaires.In recent years,although more and more attention has been paid to proactive aggression.At present,the research on proactive aggression remain scarce,especially on the brain basis of proactive aggression.Neural basis of the proactive aggression remain unclear.There are two main reasons for this problem.The first reason is the lack of theorety of proactive aggression,especially the lack of theory that can effectively guide and explain the brain basis of proactive aggression.The second reason is that there is not experimental task that can be used to study the neural basis of proactive aggression.In view of the above problems,this paper first constructed the motivation theory of proactive aggression and developed an effective and reliable laboratory-based tasks of proactive aggression,namely reward-interference task(Study 1);at the same time,the neural basis of proactive aggression is investigated comprehensively by combining state-based proactive aggression measured by reward-interference task(RIT)and trait-based proactive aggression measured by questionnaires(Study 2 and Study 3).Study 1 includes four experiments.Experiment 1 examined the motivations in the RIT by interview.And the results shows RIT involves instrumental motivation,moral disengagement and moral inhibition.Experiment 2 develop the task-related motivation questionnaire(Interference/Noninterference Motivations Questionnaire,INIMQ)based on the results of the interviews in Experiment 1 and the previous study and test the reliability and construct validity of the questionnaires.The reliability and validity of the RIT was sought to examine.Results suggested the validity and reliability of the INIMQ were acceptable.The RIT had good internal consistency,adequate convergence,and discriminant validity.In experiment 3,the validity of reward-interference task was further tested using INIMQ and non-incentive proactive aggression and reactive aggression measured by Taylor's Aggression Paradigm.The results showed that incentive proactive aggression measured by RIT was positively correlated with instrumental aggression,nonincentive proactive aggression and moral disengagement,negatively correlated with moral inhibition.Incentive proactive aggression measured by RIT were not significantly correlated with the reactive aggression.These results further supported the validity of reward-interference task.Experiment 4 explored the effect of the size of the reward on the proactive aggression.The findings demonstrated that rewards as an important incentive played a key role in aggression in the RIT.Participants tended to implement more aggressive behavior with the increase of rewards in the RIT.The results of these four experiments showed that the internal consistency reliability and validity of the RIT were good.The task can trigger the proactive aggression behavior and motivation(i.e.,reward motivation and moral motivation).The reliability and validity of the INIMQ questionnaire are good.It can effectively measure the motivation of proactive aggression in the experiment.In a word,RIT is a valid tool for inducing and measuring proactive aggression behavior under incentive(reward)conditions.It has obvious advantages compared with the existing experimental tasks of proactive aggression.The task will promote the experimental study of proactive aggression and provides a valid tool for the neural basic research of proactive aggression.Study 2 study the neural basis of state-based proactive aggression by using RIT.There are three experiments(experiment 5-experiment 7).In experiment 5,the brain activiation of proactive aggression under medium injury conditions were studied.The results showed that the common brain regions activated by both attack-selection and nonattack selection included anterior cingulate(ACC),middle cingulate(MCC),medial prefrontal lobe(MPFC),ventrolateral frontal lobe(VLPFC),infratemporal(ITM),TPJ,auxiliary motor area(SMA),orbital frontal lobe(OFG),caudate.There was no significant brain regions activation in under attack selection condition,compared with non-attack selection condition.The results of multi-regions physiological-psychological interaction(PPI)showed that compared with the neutral conditions,the connections between the right ventrolateral prefrontal cortex(VLPFC)and the calcarine gyrus,between the left VLPFC and the calcarine gyrus,supramarginal gyrus(SMG),between the medial prefrontal cortex and the calcarine gyrus,the right temporoparietal junction(TPJ),between the right temporal pole(TP)and the calcarine gyrus,the supramarginal gyrus(SMG),the right orbital frontal cortex(OFC),between the left temporal pole and the right orbital frontal cortex,between the right temporal-parietal junction and the right orbital frontal cortex were stronger and the connection between the left orbital frontal cortex and ACC is weaker under the non-attack selection condition.Compared with the neutral condition,the connections between the right temporal pole and the SMG,the right TPJ,the inferior temporal gyrus(ITG),right orbitofrontal cortex(OFC),between the right TPJ and left temporal pole,beween the left temporal pole and OFC,left TPJ,between ITG and right OFC were weaker under attack condition.The results showed that both aggression and non-aggression might involve moral cognition and emotion-related brain regions,reward-related brain regions and cognitive control-related brain regions.And the moral inhibition motivation under non-aggression conditions may be relatively stronger.Moral inhibition motivation might be relatively weaker.Experiments 6 explored the neural mechanism of proactive aggression under medium to high injury conditions.To some extent,the results of Experiment 5 are repeated.Both the attack selection and the non-attack selection involveed moral-related brain areas,reward-related brain areas and cognitive control-related brain areas.Compared with the non-attack section,the attack selection significantly activated the medial prefrontal lobe(MPFC),dorsolateral prefrontal cortex(DLPFC),anterior cingulate cortex(ACC),medium cingulate cortex(MCC),OFC,middle temporal(MTG),SMG/IPL,insula,parahippocompal gyrus,precuneus,angular gyrus and inferior frontal triangle(IFG_Tri).Compared with the neutral condition,the connection between TPJ and precuneus was stronger under the nonattack condition,and the connection between TPJ and IFG_Tri was weaker under the attack condition.Compared with the non-attack condition,the connection between IFG_Tri and the parahippocompal gyrus was weaker under the attack condition.In experiment 7,we explored the brain mechanism of injury intensity under proactive aggression.The results showed that the activation of MPFC increased with the level of attack selection.These results suggested that proactive aggression involves instrumental motivation,moral inhibition and moral disengagement,and that these three motivations are interact to determine the attack selection.Study 3 investigated the brain structures and functional connectivity underlying trait proactive aggression.Study 3 investigated brain structures and functional networks related to trait proactive aggression in the 240 samples by combining structural(grey matter density,GMD)and functional(resting-state functional connection,RSFC)fMRI.Results showed that individual differences in trait proactive aggression were positively associated with GMD in bilateral dorsolateral prefrontal cortex(DLPFC)and negatively correlated with GMD in posterior cingulate cortex(PCC);they were also negatively correlated with the strength of functional connectivity between left PCC and other brain regions,including right DLPFC,right IPL,right MPFC/ACC,and bilateral precuneus.In this study,the neural basis of proactive aggression was explored comprehensively by using multi-modal fMRI from two aspects of state and trait.These results suggested that the activation of reward system(instrumental motivation),moral cognitive and moral emotional system(moral inhibition),moral system and cognitive control system(moral disengagement)related brain areas were involved in proactive aggression.The individual difference of trait proactive aggression has its brain basis.Tait proactive aggression was related to moral cognition and emotion-related brains,moral cognitive and emotional regulation-related brains.These findings revealed the brain basis of proactive aggression for the first time,and proposed a processing model of proactive aggression at the neural system level based on these results,which is of great significance for us to understand the process of proactive aggression.At the same time,the study can provide a certain guiding role in the prevention and counseling and intervention for proactive aggression.