Pheromone responsiveness threshold depends on temporal integration by antennal lobe projection neurons
Pheromone responsiveness threshold depends on temporal integration by antennal lobe projection neurons
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DOI：
10.1073/pnas.1313707110
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发表时间：
2013-09-17
影响因子：
11.1
通讯作者：
Kanzaki, Ryohei
中科院分区：
文献类型：
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作者：
Tabuchi, Masashi;Sakurai, Takeshi;Kanzaki, Ryohei
雄蛾的嗅觉系统具有极高的灵敏度，能够探测和识别散布在空气中的、被大大稀释的同种信息素。只要170个分子的蚕蛾性信息素就足以诱导雄性的性行为。然而，目前还不清楚嗅觉受体神经元（ORN）的敏感性是如何通过大脑传递以产生高行为反应的。在这里，我们表明，ORN活动是阈下的行为，可以放大到阈上水平的触角叶投射神经元（PN）的时间整合，如果发生在一个特定的时间窗口。为了控制具有高时间分辨率的ORN输入，将通道视紫红质-2遗传引入到家蚕酚响应的ORN中。PN的时间整合只观察到弱输入，但没有强输入。药理学解剖显示，GABA能机制抑制强输入的时间整合，表明GABA信号以刺激依赖的方式调节PN反应。我们的研究结果表明，通过嗅觉信息的时间整合来增强PN的反应特别发生在行为阈值附近，有效地定义了行为反应的下限。
The olfactory system of male moths has an extreme sensitivity with the capability to detect and recognize conspecific pheromones dispersed and greatly diluted in the air. Just 170 molecules of the silkmoth (Bombyx mori) sex pheromone bombykol are sufficient to induce sexual behavior in the male. However, it is still unclear how the sensitivity of olfactory receptor neurons (ORNs) is relayed through the brain to generate high behavioral responsiveness. Here, we show that ORN activity that is subthreshold in terms of behavior can be amplified to suprathreshold levels by temporal integration in antennal lobe projection neurons (PNs) if occurring within a specific time window. To control ORN inputs with high temporal resolution, channelrhodopsin-2 was genetically introduced into bombykol-responsive ORNs. Temporal integration in PNs was only observed for weak inputs, but not for strong inputs. Pharmacological dissection revealed that GABAergic mechanisms inhibit temporal integration of strong inputs, showing that GABA signaling regulates PN responses in a stimulus-dependent fashion. Our results show that boosting of the PNs' responses by temporal integration of olfactory information occurs specifically near the behavioral threshold, effectively defining the lower bound for behavioral responsiveness.