Converging Circuits Mediate Temperature and Shock Aversive Olfactory Conditioning in Drosophila
Converging Circuits Mediate Temperature and Shock Aversive Olfactory Conditioning in Drosophila
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DOI：
10.1016/j.cub.2014.06.062
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发表时间：
2014-08-04
期刊：
影响因子：
9.2
通讯作者：
Tanimoto, Hiromu
中科院分区：
文献类型：
--
作者：
Galili, Dana Shani;Dylla, Kristina V.;Tanimoto, Hiromu
背景：果蝇学会避免与令人厌恶的刺激配对的气味。电击是一种强烈的厌恶刺激，通过多巴胺神经元引起对相关气味的回避。虽然多巴胺信号已被证明可以介导嗅觉电击调节，但尚不清楚这一途径如何参与其他类型的行为强化，例如在温度升高的情况下习得性地避免气味。结果：为了更好地理解不同的厌恶强化信号的神经机制，我们在这里建立了一个嗅觉温度调节实验，可与嗅觉电击调节相媲美。我们发现交流神经元是表达dTrpA1的内部热感受器，有选择性地需要气味-温度记忆，而不是气味-冲击记忆。此外，这些单独的温度升高和电击的感觉通路汇聚到重叠的多巴胺神经元群上，这些多巴胺神经元发出厌恶强化的信号。温度调节似乎需要电击调节所需的多巴胺神经元的一个子集。结论：多巴胺神经元将不同的有害信号整合到一个普遍的厌恶强化通路中。
Background: Drosophila learn to avoid odors that are paired with aversive stimuli. Electric shock is a potent aversive stimulus that acts via dopamine neurons to elicit avoidance of the associated odor. While dopamine signaling has been demonstrated to mediate olfactory electric shock conditioning, it remains unclear how this pathway is involved in other types of behavioral reinforcement, such as in learned avoidance of odors paired with increased temperature.Results: To better understand the neural mechanisms of distinct aversive reinforcement signals, we here established an olfactory temperature conditioning assay comparable to olfactory electric shock conditioning. We show that the AC neurons, which are internal thermal receptors expressing dTrpA1, are selectively required for odor-temperature but not for odor-shock memory. Furthermore, these separate sensory pathways for increased temperature and shock converge onto overlapping populations of dopamine neurons that signal aversive reinforcement. Temperature conditioning appears to require a subset of the dopamine neurons required for electric shock conditioning.Conclusions: We conclude that dopamine neurons integrate different noxious signals into a general aversive reinforcement pathway.