Thermosensory processing in the Drosophila brain.
Thermosensory processing in the Drosophila brain.
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DOI：
10.1038/nature14170
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发表时间：
2015-03-19
期刊：
影响因子：
64.8
通讯作者：
Wilson RI
中科院分区：
文献类型：
--
作者：
Liu WW;Mazor O;Wilson RI
在果蝇中，就像在脊椎动物中一样，外部温度的变化是由双向相反的热感受器细胞编码的：一些细胞因变暖而兴奋，但因降温而受到抑制，而另一些细胞因变冷而兴奋，因变暖而受到抑制。处理这些信号的中央电路还不是很清楚。在果蝇中，一个特定的大脑区域接受来自温度感受器细胞的输入。在这里，我们展示了这个大脑区域中不同的基因识别的投射神经元(PN)在降温和/或升温的刺激下。冷兴奋的三叉神经节主要接受冷热感受器的前馈兴奋。相反，温热兴奋的三叉神经节(“温性三叉神经节”)既接受温热感受器的兴奋，又通过抑制性中间神经元接受冷热感受器的交叉抑制。值得注意的是，这种交叉抑制引起了升温引起的兴奋，因为升温抑制了冷热感受器的紧张性活动。这反过来又抑制了由变暖引起的前馈兴奋的暖PNS和总和。交叉抑制可以消除热感受器细胞与冷感受器细胞之间正相关的非热活动(噪声)，而增强反相关的热活动。我们的结果展示了中央电路如何结合来自双向对立神经元的信号来构造敏感和健壮的神经编码。
In Drosophila, just as in vertebrates, changes in external temperature are encoded by bidirectional opponent thermoreceptor cells: some cells are excited by warming and inhibited by cooling, whereas others are excited by cooling and inhibited by warming. The central circuits that process these signals are not understood. In Drosophila, a specific brain region receives input from thermoreceptor cells. Here we show that distinct genetically-identified projection neurons (PNs) in this brain region are excited by cooling, warming, or both. The PNs excited by cooling receive mainly feedforward excitation from cool thermoreceptors. In contrast, the PNs excited by warming (“warm-PNs”) receive both excitation from warm thermoreceptors and crossover inhibition from cool thermoreceptors via inhibitory interneurons. Notably, this crossover inhibition elicits warming-evoked excitation, because warming suppresses tonic activity in cool thermoreceptors. This in turn disinhibits warm-PNs and sums with feedforward excitation evoked by warming. Crossover inhibition could cancel non-thermal activity (noise) that is positively-correlated among warm and cool thermoreceptor cells, while reinforcing thermal activity which is anti-correlated. Our results show how central circuits can combine signals from bidirectional opponent neurons to construct sensitive and robust neural codes.