負面情緒對暴力青少年抑制能之影響：腦波研究

The effects of negative emotional states on inhibitory control in violent adolescents: an event-related potential study

暴力事件常常是因為情緒事件而引發，近來研究對於暴力行為的神經機制越感興趣，但情緒對於暴力行為的影響卻所知有限。暴力青少年常被認為缺乏衝動控制能力，本研究欲採用情緒性停止訊號作業及腦波儀，目的是想瞭解這些有暴力行為青少年如何解決情緒以及抑制控制上的衝突，觀察其行為表現及電生理指標。本研究之受試者篩選方式除了一句過去的犯罪史，亦採用反應性─主動性暴力行為問卷，來區分受試者之攻擊性類別與程度。本研究假設暴力青少年有較高的行為激發系統(behavioral activation system)活化程度，go反應時間應會變快。相反的，若是其行為抑制系統(behavioral inhibition system)功能較差，則停止訊號反應時間(stop signal reaction time, SSRT)應該會變慢，是抑制能力缺損的結果。本研究採用追蹤方式的情緒性停止訊號作業，實驗設計方式是透過對於go刺激有更快的反應速度和產生接近50%的抑制失敗錯誤率，在這樣的設計下，受試者需要投入更多的抑制控制來強烈的go反應傾向，而這對暴力青少年可能更加的困難。行為結果顯示暴力青少年犯組與對照組的go反應時間無顯著差異，實驗組的SSRT顯著地比對照組長，實驗組的抑制行為的能力可能較差。腦波資料也顯示，負面情緒下，實驗組在成功抑制時的N1高於失敗抑制時的N1，但控制組並無顯著差異，顯示暴力青少年需要投注了較多的注意力資源，才能抑制成功。控制組在負面情緒時的P3振幅顯著大於中性情緒，而實驗組並無顯著差異。本研究表明衝動型暴力青少年可能有抑制控制上的缺陷，這可能是由於情緒可調控投注在刺激上的大腦資源。與控制組不同，電生理資料顯示情緒性刺激並沒有調控衝動型暴力青少年抑制功能。

Interpersonalviolentbehaviorisofteninducedbyextremeemotionalstates.Whilethereisincreasinginterestintheneurologicalbasesofthisbehavior,theeffectsofemotiononsuchbehaviorarepoorlyunderstood.Repeatedlyviolentadolescentsareoftendescribedashavingimpairedimpulsecontrol.Inthisstudy,anemotionalstopsignaltaskinconjunctionwithevent-relatedpotential(ERP)recordingwasusedtoexaminetheeffectsofnegativeemotiononinhibitorycontrolinindividualswithreactiveaggressionandinnormaladolescents.Thestop-signaltaskwasusedtoexamineinhibitorycontrolinadolescentswithimpulsiveviolentbehaviorandcomparedtothosewithoutviolentbehavior.Subjectswerecategorizednotonlybasedonpastcriminalhistory,butalsoonReactiveProactiveAggressionQuestionnairescores.Impulsiveviolentbehaviorcouldbeaconsequenceofeitheragreatertendencytogeneratepre-potentresponsesoradeficitininhibitionofsuchresponses.Comparedwithmatchedcontrols,ifweconsiderthatviolentadolescentsmaybecharacterizedbyhigherbehavioralactivationsystemactivity,thegoRTsinthestopsignaltaskfortheseindividuals,ameasureofimpulsivity,wouldbeexpectedtodecrease.Incontrast,ifviolentadolescentsarecharacterizedbylowerbehavioralinhibitionsystemactivity,theSSRTofviolentadolescents,whichindexesinhibitorycontrol,mightbeexpectedtoincrease.Furthermore,thetaskdesignmaycausethesubjectstodevelopanimpulsiveresponsestylecharacterizedbyfasterreactiontimestogostimuliandmaintaincloseto50%unsuccessfulinhibitedresponses.Insuchasituation,thesubjectswouldneedtorecruitmoreinhibitorycontroltoovercomethestrongergoresponsetendency.ResultsobtainedshowedthattheSSRTsofimpulsiveviolentadolescentsweresignificantlylongerthanthoseofmatchedcontrolsintheneutralemotioncondition.Theresultsofevent-relatedpotentialanalysisfortheviolentadolescentsshowedtheN1amplitude,anindicatorofattentionalengagementbythestimulus,forsuccessfulinhibitionwashigherthanforfailedinhibitiontrialsinthenegativeemotioncondition.Thisdifferencewasnotseenforthecontrolsubjects.TheP3amplitudefortheemotionalcondition,anindicatorofinhibitoryability,washigherthanfortheneutralconditiononlyforthecontrolsubjects.Thisstudyshowsimpulsiveviolentadolescentsmayhavedeficitsininhibitorycontrolasaconsequenceofengagementwiththestimuliandwhichcanbemodulatedbyemotionalinformation.Unlikecontrols,theemotionalinformationproducednomodulationofelectrophysiologicalactivityrelatedtoinhibitorycontrolforviolentindividuals.