“忽冷忽热”的杏仁核:与攻击相关的重要核团

The“cold and hot”amygdala:An important nucleus relative to aggression

攻击是有意对他人造成直接伤害的行为,可以分为反应性攻击和主动性攻击。攻击行为的发生有其神经生理基础,作为情绪加工和学习的关键脑区,杏仁核与攻击有着密切的关联。战斗-逃跑机制模型、暴力抑制机制模型和恐惧功能障碍假说强调了杏仁核对于攻击的重要性。表现出攻击或暴力行为的群体存在杏仁核的结构缺陷和功能障碍,其中功能障碍有两种相反的异常表现:在具有反应性攻击表现的高危人群中,杏仁核对威胁性刺激的反应增强(“热”反应);而以主动性攻击为主的人群如带有冷酷无情特质的精神病态人群,会表现出对威胁性刺激以及他人痛苦情绪线索的杏仁核反应减弱,以及在恐惧条件学习和道德决策的过程中杏仁核的激活不足的现象(“冷”反应)。这些功能障碍损害了个体在威胁反应、共情能力、惩罚回避以及道德决策等方面的正常水平。未来研究需人群研究和过程研究并举,关注杏仁核子结构的功能,探究攻击的神经网络基础,并探索有效的暴力防治干预手段。

Aggression can be defined as any behavior directed toward another with the intent to cause direct harm.It can be divided into reactive aggression and proactive aggression.Aggression has an underlying neurophysiological basis.As a key region of emotion processing and learning,the amygdala is closely associated with aggression.The fight-flight mechanism,the violence inhibition mechanism and the fear dysfunction hypothesis emphasize the importance of the amygdala for aggression.Structural deficits and dysfunctions of the amygdala have been observed in individuals who display aggressive or violent behaviors,with two different abnormal manifestations.In groups with high risk of reactive aggression,the amygdala’s response to threatening stimuli is enhanced(a“hot”response).However,in proactive aggression,exhibited by individuals with psychopathic and callous-unemotional traits,researches have reported diminished amygdala responses to threatening stimuli and others’distress cues as well as insufficient activation of the amygdala during fear conditioning learning and moral decision-making(a“cold”response).These dysfunctions might impair the normal function of individuals in terms of threat response,empathy,punishment avoidance and moral decision-making.Future research should focus on both population and processes,give more attention to the functions of the amygdala’s substructures,explore the neural network associated with aggression,and investigate effective interventions to prevent violence.