Number of types of olfactory receptors

Range ~400 types
Organism Human Homo sapiens
Reference Meister M., On the dimensionality of odor space. Elife. 2015 Jul 7 4 :e07865. doi: 10.7554/eLife.07865. P.1 bottom paragraphPubMed ID26151672
Primary Source Malnic B, Godfrey PA, Buck LB. 2004. The human olfactory receptor gene family. Proceedings of the National Academy of Sciences of USA 101: 2584–2589. doi: 10.1073/pnas.0307882100.PubMed ID14983052
Comments P.1 bottom paragraph: "One would like to achieve a similarly satisfying understanding of human smell [as that of color perception]. Human olfaction begins with the binding of odor molecules to olfactory receptors, of which there exist ∼400 types (primary source). It is believed that these receptor types all differ in their relative sensitivity to various odorants. Two odors can only be distinguished if they cause different patterns of activity among these types. Thus the neural space of odors at the very input to the olfactory system would seem to have 400 dimensions, many more than encountered in the color system. But what is the perceptual space for odors? The exact analog of the early color mixing experiments has not been done, but from a quantitative analysis of perceptual similarities it has been argued that the space of odors is dominated by just one or two dimensions (Secundo et al., 2014), much fewer than the 400 dimensions at the level of sensory receptors."
Entered by Uri M
ID 112608