Courtiol Emmanuelle, Lefèvre Laura, Garcia Samuel, Thévenet Marc, Messaoudi Belkacem, Buonviso Nathalie
Centre de Recherche en Neurosciences de Lyon, Equipe Olfaction: du codage à la mémoire, CNRS UMR 5292-INSERM U1028-Université Lyon1 Lyon, France.
Front Behav Neurosci. 2014 May 5;8:145. doi: 10.3389/fnbeh.2014.00145. eCollection 2014.
A growing body of evidence suggests that sniffing is not only the mode of delivery for odorant molecules but also contributes to olfactory perception. However, the precise role of sniffing variations remains unknown. The zonation hypothesis suggests that animals use sniffing variations to optimize the deposition of odorant molecules on the most receptive areas of the olfactory epithelium (OE). Sniffing would thus depend on the physicochemical properties of odorants, particularly their sorption. Rojas-Líbano and Kay (2012) tested this hypothesis and showed that rats used different sniff strategies when they had to target a high-sorption (HS) molecule or a low-sorption (LS) molecule in a binary mixture. Which sniffing strategy is used by rats when they are confronted to discrimination between two similarly sorbent odorants remains unanswered. Particularly, is sniffing adjusted independently for each odorant according to its sorption properties (analytical processing), or is sniffing adjusted based on the pairing context (synthetic processing)? We tested these hypotheses on rats performing a two-alternative choice discrimination of odorants with similar sorption properties. We recorded sniffing in a non-invasive manner using whole-body plethysmography during the behavioral task. We found that sniffing variations were not only a matter of odorant sorption properties and that the same odorant was sniffed differently depending on the odor pair in which it was presented. These results suggest that rather than being adjusted analytically, sniffing is instead adjusted synthetically and depends on the pair of odorants presented during the discrimination task. Our results show that sniffing is a specific sensorimotor act that depends on complex synthetic processes.
越来越多的证据表明，吸气不仅是气味分子的传递方式，而且对嗅觉感知也有贡献。然而，吸气变化的确切作用仍然未知。分区假说认为，动物利用吸气变化来优化气味分子在嗅觉上皮（OE）最敏感区域的沉积。因此，吸气将取决于气味剂的物理化学性质，特别是它们的吸附作用。罗哈斯 - 利巴诺和凯（2012年）对这一假说进行了测试，结果表明，当大鼠必须在二元混合物中靶向高吸附（HS）分子或低吸附（LS）分子时，它们会使用不同的吸气策略。当大鼠面临两种吸附性相似的气味剂之间的辨别时，它们会使用哪种吸气策略仍未得到解答。特别是，吸气是根据每种气味剂的吸附特性独立调整（分析处理），还是根据配对背景进行调整（综合处理）？我们在对具有相似吸附特性的气味剂进行二选一辨别任务的大鼠身上测试了这些假说。在行为任务期间，我们使用全身体积描记法以非侵入性方式记录吸气情况。我们发现，吸气变化不仅与气味剂的吸附特性有关，而且相同的气味剂根据其呈现的气味对不同而被不同地吸气。这些结果表明，吸气不是通过分析进行调整，而是通过综合调整，并且取决于辨别任务期间呈现的气味对。我们的结果表明，吸气是一种特定的感觉运动行为，取决于复杂的综合过程。
