Computational Mechanics Division, Applied Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA.
Chem Senses. 2012 Jul;37(6):553-66. doi: 10.1093/chemse/bjs039. Epub 2012 Apr 2.
Olfaction begins when an animal draws odorant-laden air into its nasal cavity by sniffing, thus transporting odorant molecules from the external environment to olfactory receptor neurons (ORNs) in the sensory region of the nose. In the dog and other macrosmatic mammals, ORNs are relegated to a recess in the rear of the nasal cavity that is comprised of a labyrinth of scroll-like airways. Evidence from recent studies suggests that nasal airflow patterns enhance olfactory sensitivity by efficiently delivering odorant molecules to the olfactory recess. Here, we simulate odorant transport and deposition during steady inspiration in an anatomically correct reconstructed model of the canine nasal cavity. Our simulations show that highly soluble odorants are deposited in the front of the olfactory recess along the dorsal meatus and nasal septum, whereas moderately soluble and insoluble odorants are more uniformly deposited throughout the entire olfactory recess. These results demonstrate that odorant deposition patterns correspond with the anatomical organization of ORNs in the olfactory recess. Specifically, ORNs that are sensitive to a particular class of odorants are located in regions where that class of odorants is deposited. The correlation of odorant deposition patterns with the anatomical organization of ORNs may partially explain macrosmia in the dog and other keen-scented species.
嗅觉始于动物通过嗅探将含有气味的空气吸入鼻腔，从而将气味分子从外部环境运输到鼻子感觉区域的嗅觉受体神经元（ORNs）。在狗和其他大嗅觉哺乳动物中，ORNs 局限于鼻腔后部的一个凹陷处，该凹陷处由一系列盘旋的气道组成。最近的研究证据表明，通过有效地将气味分子输送到嗅觉凹陷处，鼻腔气流模式可增强嗅觉敏感性。在这里，我们在犬鼻腔的解剖学上重建模型中模拟了稳定吸气期间气味的传输和沉积。我们的模拟表明，高可溶性气味物质沿着背道和鼻中隔沉积在嗅觉凹陷的前部，而中等可溶性和不溶性气味物质则更均匀地沉积在整个嗅觉凹陷处。这些结果表明，气味沉积模式与嗅觉凹陷处 ORNs 的解剖组织相对应。具体而言，对特定类别的气味敏感的 ORNs 位于该类别气味沉积的区域。气味沉积模式与 ORNs 的解剖组织的相关性可能部分解释了狗和其他嗅觉灵敏的物种的大嗅觉现象。
