Striatal dopamine release and motivated behavior

这个项目的目的是确定纹状体多巴胺释放在动机和强化中的作用。最近，我们发现化学刺激的乳头上核是加强在大鼠，这表明乳头上核可能是一个组成部分的初级强化。由于腹侧纹状体中的多巴胺释放与初级强化有关，我们研究了电刺激乳头体上核是否会增强腹侧纹状体中的多巴胺释放，如伏安信号所示。老鼠学会了用200微安左右的电流在乳头体上核进行短时间的电刺激。电列车，支持有力的自我刺激在suprammillary区诱导多巴胺释放所示的伏安信号。乳头体上刺激诱发的多巴胺信号的时间模式与腹侧被盖刺激诱发的多巴胺信号的时间模式基本相同。这些结果表明，乳头体上的刺激触发多巴胺释放腹侧纹状体，这已牵连在初级强化，和乳头体上核是与中脑边缘多巴胺系统相关的奖励电路的一部分。

The aim of this project is to determine the role of striatal dopamine release in motivation and reinforcement. Recently, we found that chemical stimulation of the supramammillary nucleus is reinforcing in rats, suggesting that the supramammillary nucleus may be a component of primary reinforcement. Since dopamine release in the ventral striatum has been implicated in primary reinforcement, we examined whether electrical stimulation of supramammillary nucleus is reinforcing and evokes dopamine release in the ventral striatum as shown by voltammetric signals. Rats learned to lever-press to deliver brief trains of electrical stimulation at the supramammillary nucleus with currents around 200 micro A. Electrical trains that support vigorous self-stimulation at the supramammillary area induced dopamine released as indicated by voltammetric signals. Temporal patterns of dopamine signals evoked by supramammillary stimulation are essentially identical to those of evoked by ventral tegmental stimulation. These results suggest that supramammillary stimulation triggers dopamine release in the ventral striatum, which has been implicated in primary reinforcement, and that the supramammillary nucleus is part of the reward circuitry associated with the meso-limbic dopamine system.