Ventral striatal dopamine is thought to be important for associative learning. Dopamine exerts its role via activation of dopamine D1 and D2 receptors in the ventral striatum. Upregulation of dopamine D2R in the indirect pathway of the nucleus accumbens (NAc) impairs incentive motivation via inhibiting synaptic transmission to the ventral pallidum. Here, we determined whether upregulation of D2Rs and the resulting impairment in indirect pathway function modulates associative learning in an auditory Pavlovian reward learning task as well as Go/No-Go learning in an operant based reward driven Go/No-Go task. We found that upregulation of D2Rs in indirect pathway neurons of the NAc did not affect Pavlovian learning or the extinction of Pavlovian responses, and neither did it alter No-Go learning. A delay in the Go component of the task however could indicate a deficit in learning though it may be attributed to locomotor hyperactivity of the mice. In combination with previously published findings our data suggest that D2Rs in the NAc core play a specific role in regulating motivation by balancing cost/benefit computations but do not necessarily affect associative learning.

中文翻译：

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伏隔核间接途径中的多巴胺D2R上调不会影响巴甫洛夫病或Go / No-Go学习

腹侧纹状体多巴胺被认为对于联想学习很重要。多巴胺通过激活腹侧纹状体中的多巴胺D1和D2受体发挥其作用。伏伏核（NAc）间接途径中的多巴胺D2R上调通过抑制突触传递至腹侧苍白球而削弱了刺激动机。在这里，我们确定D2Rs的上调和间接通路功能的损伤是否调节听觉巴甫洛夫式奖励学习任务中的联想学习以及基于操作者的奖励驱动的“去/不去”任务中的“去/不去”学习。我们发现NAc的间接途径神经元中的D2Rs上调不会影响巴甫洛夫式学习或巴甫洛夫式反应的消失，并且也不会改变No-Go学习。尽管该任务的执行组件延迟，但可能表明学习不足，尽管这可能归因于小鼠运动过度活跃。结合先前发表的发现，我们的数据表明，NAc核心中的D2R通过平衡成本/收益计算而在调节动力方面起特定作用，但不一定会影响联想学习。