Carelli Regina M
Department of Psychology, The University of North Carolina at Chapel Hill, CB# 3270, Davie Hall, Chapel Hill, NC 27599-3270, USA.
Neuropharmacology. 2004;47 Suppl 1:180-9. doi: 10.1016/j.neuropharm.2004.07.017.
The nucleus accumbens (Acb) is a key neural substrate underlying goal-directed behaviors for both drugs of abuse as well as 'natural' rewards. Here, I review electrophysiological and electrochemical studies completed in our laboratory that examined Acb cell firing and rapid dopamine signaling during behaviors directed toward reward procurement. Electrophysiological studies are reviewed showing that Acb neurons exhibit patterned discharges relative to operant responding for intravenous self-administration of cocaine versus 'natural' reinforcement in rodents. Importantly, subsequent studies showed that discrete subsets of Acb neurons are selectively activated during multiple schedules for a natural reward (water or food) versus cocaine self-administration. These later findings indicate that separate neural circuits selectively process information about goal-directed behaviors for cocaine versus natural reward. In addition, recent findings are reviewed showing that reinforcer selective firing of Acb neurons is not a direct consequence of chronic drug exposure. Next, electrochemical studies are summarized that used fast scan cyclic voltammetry to measure rapid (subsecond) changes in dopamine in the Acb during cocaine self-administration as well as 'natural' reinforcement in rodents. These findings are considered with respect to the role of dopamine in modulating the activity of Acb neurons that encode goal-directed behaviors, the functional organization of the Acb on a microcircuit level, and proposed directions for future studies.
伏隔核（Acb）是介导滥用药物和“天然”奖赏的目标导向行为的关键神经基质。在此，我回顾了在我们实验室完成的电生理和电化学研究，这些研究考察了在指向奖赏获取行为过程中伏隔核细胞的放电情况以及多巴胺的快速信号传递。回顾了电生理研究，结果表明相对于啮齿动物静脉内自我注射可卡因的操作性反应和“天然”强化，伏隔核神经元表现出模式化放电。重要的是，后续研究表明，在多种自然奖赏（水或食物）与可卡因自我给药的实验安排中，伏隔核神经元的离散亚群被选择性激活。这些后来的发现表明，不同的神经回路选择性地处理关于可卡因与天然奖赏的目标导向行为的信息。此外，回顾了最近的研究发现，表明伏隔核神经元对强化物的选择性放电不是长期药物暴露的直接结果。接下来，总结了电化学研究，这些研究使用快速扫描循环伏安法来测量啮齿动物在可卡因自我给药以及“天然”强化过程中伏隔核内多巴胺的快速（亚秒级）变化。结合多巴胺在调节编码目标导向行为的伏隔核神经元活动中的作用、伏隔核在微回路水平上的功能组织以及未来研究的建议方向，对这些发现进行了探讨。
