THE INVOLVEMENT OF NUCLEUS-ACCUMBENS DOPAMINE IN APPETITIVE AND AVERSIVE MOTIVATION

In recent years, considerable emphasis has been placed upon the putati ve role of nucleus accumbens dopamine systems in appetitive motivation and positive reinforcement. However, considerable evidence indicates that brain dopamine in general, and nucleus accumbens dopamine in part icular, is involved in aspects of aversive motivation. Administration of dopamine antagonists or localized interference with nucleus accumbe ns dopamine systems has been shown to disrupt active avoidance behavio r. In addition, accumbens dopamine release and metabolism is activated by a wide variety of stressful conditions. A review of the literature indicates that there are substantial similarities between the charact eristics of dopaminergic involvement in appetitive and aversive motiva tion. There is conflicting evidence about the role of dopamine in emot ion, and little evidence to suggest that the profound and consistent c hanges in instrumental behavior produced by interference with DA syste ms are due to direct dopaminergic mediation of positive affective resp onses such as hedonia. It is suggested that nucleus accumbens dopamine is involved in aspects of sensorimotor functions that are involved in both appetitive and aversive motivation.