Light-induced activation of distinct modulatory neurons triggers appetitive or aversive learning in Drosophila larvae
Light-induced activation of distinct modulatory neurons triggers appetitive or aversive learning in Drosophila larvae
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DOI：
10.1016/j.cub.2006.07.023
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发表时间：
2006-09-05
期刊：
影响因子：
9.2
通讯作者：
Fiala, Andre
中科院分区：
文献类型：
--
作者：
Schroll, Christian;Riemensperger, Thomas;Fiala, Andre
在经典条件反射中，一个积极或消极的价值被分配给一个先前中性的刺激，从而改变了它对行为的意义。如果一种气味与负面刺激有关，它会变得令人厌恶。相反，与奖励相关的气味可能会变得有吸引力。通过使用果蝇幼虫作为一个模型系统与最小的大脑复杂性，我们解决的问题，这些值的神经元的气味刺激。在昆虫中，多巴胺能神经元是厌恶学习所必需的，而章鱼胺能神经元是食欲学习所必需和充分的[1-4]。然而，目前尚不清楚两个独立的神经元群体是否足以介导这种拮抗作用。我们报告了使用转基因表达的通道视紫红质-2（channelrhodopsin-2）[5]（一种光激活阳离子通道）作为果蝇幼虫中遗传定义的神经元群体的光生理刺激工具。我们证明，不同的神经元群体可以简单地通过用蓝光照射动物来激活。光诱导的多巴胺能神经元的激活与气味刺激配对诱导厌恶性记忆形成，而章鱼胺能/酪胺能神经元的激活诱导食欲记忆形成。这些发现表明，拮抗性调节子系统足以取代经典条件反射过程中的厌恶和食欲强化。
During classical conditioning, a positive or negative value is assigned to a previously neutral stimulus, thereby changing its significance for behavior. If an odor is associated with a negative stimulus, it can become repulsive. Conversely, an odor associated with a reward can become attractive. By using Drosophila larvae as a model system with minimal brain complexity, we address the question of which neurons attribute these values to odor stimuli. In insects, dopaminergic neurons are required for aversive learning, whereas octopaminergic neurons are necessary and sufficient for appetitive learning [1-4]. However, it remains unclear whether two independent neuronal populations are sufficient to mediate such antagonistic values. We report the use of transgenically expressed channelrhodopsin-2 [5], a light-activated cation channel, as a tool for optophysiological stimulation of genetically defined neuronal populations in Drosophila larvae. We demonstrate that distinct neuronal populations can be activated simply by illuminating the animals with blue light. Light-induced activation of dopaminergic neurons paired with an odor stimulus induces aversive memory formation, whereas activation of octopaminergic/tyraminergic neurons induces appetitive memory formation. These findings demonstrate that antagonistic modulatory subsystems are sufficient to substitute for aversive and appetitive reinforcement during classical conditioning.