Depue R A, Collins P F
Department of Human Development, Laboratory of Neurobiology of Personality and Emotion, Cornell University, Ithaca, NY 14853, USA.
Behav Brain Sci. 1999 Jun;22(3):491-517; discussion 518-69. doi: 10.1017/s0140525x99002046.
Extraversion has two central characteristics: (1) interpersonal engagement, which consists of affiliation (enjoying and valuing close interpersonal bonds, being warm and affectionate) and agency (being socially dominant, enjoying leadership roles, being assertive, being exhibitionistic, and having a sense of potency in accomplishing goals) and (2) impulsivity, which emerges from the interaction of extraversion and a second, independent trait (constraint). Agency is a more general motivational disposition that includes dominance, ambition, mastery, efficacy, and achievement. Positive affect (a combination of positive feelings and motivation) is closely associated with extraversion. Extraversion is accordingly based on positive incentive motivation. Parallels between extraversion (particularly its agency component) and a mammalian behavioral approach system based on positive incentive motivation implicate a neuroanatomical network and modulatory neurotransmitters in the processing of incentive motivation. A corticolimbic-striatal-thalamic network (1) integrates the salient incentive context in the medial orbital cortex, amygdala, and hippocampus; (2) encodes the intensity of incentive stimuli in a motive circuit composed of the nucleus accumbens, ventral pallidum, and ventral tegmental area dopamine projection system; and (3) creates an incentive motivational state that can be transmitted to the motor system. Individual differences in the functioning of this network arise from functional variation in the ventral tegmental area dopamine projections, which are directly involved in coding the intensity of incentive motivation. The animal evidence suggests that there are three neurodevelopmental sources of individual differences in dopamine: genetic, "experience-expectant," and "experience-dependent." Individual differences in dopamine promote variation in the heterosynaptic plasticity that enhances the connection between incentive context and incentive motivation and behavior. Our psychobiological threshold model explains the effects of individual differences in dopamine transmission on behavior, and their relation to personality traits is discussed.
（1）人际参与，包括亲和性（享受并重视亲密的人际关系纽带，热情且深情）和能动性（在社交中占主导地位，享受领导角色，坚定自信，爱表现，在实现目标时有掌控感）；（2）冲动性，它源自外向性与另一个独立特质（约束性）的相互作用。能动性是一种更普遍的动机倾向，包括支配性、野心、掌控力、效能感和成就感。积极情感（积极情绪和动机的结合）与外向性密切相关。因此，外向性基于积极的激励动机。外向性（尤其是其能动性成分）与基于积极激励动机的哺乳动物行为趋近系统之间的相似之处，暗示了在激励动机处理过程中的一个神经解剖网络和调节性神经递质。一个皮质-边缘-纹状体-丘脑网络：（1）在内侧眶额皮质、杏仁核和海马体中整合显著的激励情境；（2）在由伏隔核、腹侧苍白球和腹侧被盖区多巴胺投射系统组成的动机回路中编码激励刺激的强度；（3）产生一种可传递至运动系统的激励动机状态。该网络功能的个体差异源于腹侧被盖区多巴胺投射的功能变化，这些变化直接参与对激励动机强度的编码。动物研究证据表明，多巴胺个体差异有三个神经发育来源：基因、“经验预期性”和“经验依赖性”。多巴胺的个体差异促进了异突触可塑性的变化，这种变化增强了激励情境与激励动机及行为之间的联系。我们的心理生物学阈值模型解释了多巴胺传递个体差异对行为的影响，并讨论了它们与人格特质的关系。
