Octopamine function revisited: Reward processing in Drosophila larvae

学习和记忆使动物和人类能够根据过去的经验和现在的情况及时适应行为。例如，在巴甫洛夫条件反射中，动物将感官暗示与惩罚或奖励的存在联系起来。虽然学习和记忆研究在许多生物体中都是可能的，但在过去的50年里，对果蝇的研究获得了一种特殊的势头。增强的细胞分辨率基于其遗传上易处理和数字上不那么复杂的大脑，为在分子、细胞、生理和小型神经网络水平上理解保守的学习和记忆功能提供了相当大的潜力。对果蝇的初步研究表明，多巴胺能神经元发出信号惩罚，而章鱼能神经元-章鱼胺是去甲肾上腺素信号奖励的无脊椎动物功能类似物。然而，最近的结果得出结论，不同组的多巴胺能神经元为奖赏和惩罚提供关键的指导信号。这似乎颠覆了以前的功能分离模型，限制了八胺能神经元在奖赏加工中的功能。因此，下面的问题出现了：在奖赏处理过程中，章鱼能系统到底做了什么？

Learning and memory enables animals and humans to timely adapt behavior according to past experience and present circumstances. In Pavlovian conditioning for instance, animals associate sensory cues with the presence of punishment or reward. Although learning and memory studies are possible in many organisms, research in Drosophila has gained a special momentum over the last 50 years. The enhanced cellular resolution based on its genetically tractable and numerically less complex brain provides considerable potential to understand conserved learning and memory functions at the molecular, cellular, physiological and small neural network level. Initial work in Drosophila suggested that dopaminergic neurons signal punishment and octopaminergic neurons -octopamine is the invertebrate functional analogue of norepinephrine- signals reward. However, recent results conclude that distinct sets of dopaminergic neurons provide key instructive signals for both reward and punishment. This seems to overturn the previous functionally separated model and limits the function of octopaminergic neurons in reward processing. Therefore, the following question arises: What does the octopaminergic system really do during reward processing?