Associative learning mediates dynamic shifts in dopamine signaling in the nucleus accumbens
Associative learning mediates dynamic shifts in dopamine signaling in the nucleus accumbens
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DOI：
10.1038/nn1923
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发表时间：
2007-08-01
影响因子：
25
通讯作者：
Carelli, Regina M.
中科院分区：
文献类型：
--
作者：
Day, Jeremy J.;Roitman, Mitchell F.;Carelli, Regina M.
利用环境线索预测有利结果的能力是习得行为的重要组成部分。中脑中的多巴胺神经元以与当代学习模型一致的方式编码这种刺激-奖励关系，但目前尚不清楚这种编码如何转化为目标区域的实际多巴胺释放。在这里，我们采样多巴胺水平在大鼠延髓核在一个快速（100毫秒）的时间尺度上使用电化学技术在一个经典的空调程序。在条件反射的早期，短暂的多巴胺释放事件发出了主要奖励的信号，但不是预测性的线索。在重复的线索奖励配对后，多巴胺信号及时转移到预测线索的开始，并且在奖励传递时不再观察到。在没有刺激-奖赏条件反射的情况下，多巴胺信号没有变化。与建议的奖励预测和激励显着性的作用一致，这些结果表明，多巴胺的快速释放提供了一个奖励信号，该信号是动态修改的联想学习。
The ability to predict favorable outcomes using environmental cues is an essential part of learned behavior. Dopamine neurons in the midbrain encode such stimulus-reward relationships in a manner consistent with contemporary learning models, but it is unclear how encoding this translates into actual dopamine release in target regions. Here, we sampled dopamine levels in the rat nucleus accumbens on a rapid (100 ms) timescale using electrochemical technology during a classical conditioning procedure. Early in conditioning, transient dopamine-release events signaled a primary reward, but not predictive cues. After repeated cue-reward pairings, dopamine signals shifted in time to predictive cue onset and were no longer observed at reward delivery. In the absence of stimulus-reward conditioning, there was no shift in the dopamine signal. Consistent with proposed roles in reward prediction and incentive salience, these results indicate that rapid dopamine release provides a reward signal that is dynamically modified by associative learning.