Dose-response characteristics of glomerular activity in the moth antennal lobe
Dose-response characteristics of glomerular activity in the moth antennal lobe
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DOI：
10.1093/chemse/28.4.269
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发表时间：
2003-05-01
期刊：
影响因子：
3.5
通讯作者：
Hansson, BS
中科院分区：
文献类型：
--
作者：
Carlsson, MA;Hansson, BS
气味是昆虫触角叶中被激活的小球的独特组合。受体神经元树枝状的肾小球不仅是定性的选择性，但此外，在刺激浓度的变化作出反应。由于每个肾小球可能代表一个单一的受体神经元类型，昆虫触角叶中钙变化的光学记录显示了浓度变化如何影响大量的传入神经。我们测量了肾小球反应的蛾Spodoptera littoralis不同浓度的植物相关的气味。局部钙反应显示对应于单个肾小球。我们发现，肾小球反应的动态范围跨越3-4个对数单位的浓度和最强烈的反应肾小球往往在高刺激剂量达到一个平台。此外，我们发现，单一的最活跃的肾小球往往是不一样的浓度。然而，如果主肾小球移动，它通常是相邻或近端肾小球。随着浓度的增加，更多数量的肾小球被激活。随着浓度差异的增加，不同剂量相同化合物的肾小球代表性的相关性降低。此外，由不同的气味剂引起的表征在高剂量下比在低剂量下更相关，这意味着活动模式的独特性随着浓度的增加而降低。因此，如果气味被编码为肾小球活动的空间模式，正如已经提出的那样，这些嗅觉代码在浓度范围内并不持久。
Odours are represented as unique combinations of activated glomeruli in the antennal lobes of insects. Receptor neurons arborizing in the glomeruli are not only qualitatively selective, but in addition respond to variations in stimulus concentration. As each glomerulus likely represents a single receptor neuron type, optical recordings of calcium changes in insect antennal lobes show how concentration variations affect a large population of afferents. We measured the glomerular responses in the moth Spodoptera littoralis to different concentrations of plant-related odorants. Localized calcium responses were shown to correspond to individual glomeruli. We found that the dynamic range of glomerular responses spanned 3-4 log units of concentration and the most strongly responding glomeruli often reached a plateau at high stimulus doses. Further, we showed that the single most active glomerulus was often not the same across concentrations. However, if the principal glomerulus moved, it was generally to an adjacent or proximal glomerulus. As concentration increased, a higher number of glomeruli became activated. Correlations of glomerular representations of the same compound at different doses decreased as the difference in concentration increased. Moreover, representations evoked by different odorants were more correlated at high than at low doses, which means that the uniqueness of activity patterns decreased with increasing concentration. Thus, if odours are coded as spatial patterns of glomerular activity, as has been suggested, these olfactory codes are not persistent across concentrations.