Odor-evoked neural oscillations in Drosophila are mediated by widely branching interneurons.
Odor-evoked neural oscillations in Drosophila are mediated by widely branching interneurons.
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DOI：
10.1523/jneurosci.1455-09.2009
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发表时间：
2009-07-01
期刊：
影响因子：
--
通讯作者：
Stopfer M
中科院分区：
文献类型：
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作者：
Tanaka NK;Ito K;Stopfer M
刺激诱发的神经元振荡同步已在多种物种中观察到。在这里，我们将遗传策略与来自果蝇完整大脑的配对细胞内和局部场电位（LFP）记录相结合，以研究气味诱发的神经振荡机制。我们发现自然浓度下的常见食物气味会引起蘑菇体 (MB) 的 LFP 记录中的振荡，蘑菇体是感觉整合的部位，类似于脊椎动物的梨状皮层。通过应用 GABAa 阻滞剂印防己毒素可逆地消除了振荡。触角叶（AL，类似于嗅球）内的局部和投射神经元的细胞内记录揭示了气味引发的尖峰和亚阈值膜电位振荡，这些振荡与 MB 下游记录的 LFP 振荡紧密锁相。这些结果表明，与蝗虫一样，气味可能通过局部神经元 (LN) 的 GABA 能抑制来引发 AL 神经元的振荡同步。对遗传上区分的 LN 形态的分析揭示了 AL 中的两个 GABA 能神经元群。一组 LN 支配缺乏受体神经元末端的肾小球部分，而另一组则分支更广泛，支配整个肾小球，这表明这两个群体可能参与不同的神经回路。为了测试这些 LN 的功能作用，我们使用温度敏感的动力突变基因 shibire 来有条件地、可逆地阻断来自每个或两个 LN 群体的化学传递。我们发现只有更广泛分支的 LN 群体才是产生气味引起的振荡所必需的。
Stimulus-evoked oscillatory synchronization of neurons has been observed in a wide range of species. Here, we combined genetic strategies with paired intracellular and local field potential (LFP) recordings from the intact brain of Drosophila to study mechanisms of odor-evoked neural oscillations. We found common food odors at natural concentrations elicited oscillations in LFP recordings made from the mushroom body (MB), a site of sensory integration and analogous to the vertebrate pyriform cortex. The oscillations were reversibly abolished by application of the GABAa blocker picrotoxin. Intracellular recordings from local and projection neurons within the antennal lobe (AL, analogous to the olfactory bulb) revealed odor-elicited spikes and sub-threshold membrane potential oscillations that were tightly phase-locked to LFP oscillations recorded downstream in the MBs. These results suggested that, as in locusts, odors may elicit the oscillatory synchronization of AL neurons by means of GABAergic inhibition from local neurons (LNs). An analysis of the morphologies of genetically distinguished LNs revealed two populations of GABAergic neurons in the AL. One population of LNs innervated parts of glomeruli lacking terminals of receptor neurons, whereas the other branched more widely, innervating throughout the glomeruli, suggesting the two populations might participate in different neural circuits. To test the functional roles of these LNs, we used the temperature-sensitive dynamin mutant gene, shibire, to conditionally and reversibly block chemical transmission from each or both of these populations of LNs. We found only the more widely branching population of LNs is necessary for generating odor-elicited oscillations.