Dhaka, Bangladesh
People who lack olfactory bulbs shouldn't be able to smell. But some women can

People who lack olfactory bulbs shouldn't be able to smell. But some women can

By Sofie Bates

(From previous issue) So Sobel and his colleagues had the two women and 140 others with olfactory bulbs rate the similarity of how roses, peanuts, motor oil and other scents smell. This created an "olfactory fingerprint" for each individual, giving a sense of how the world smells to that person. The results indicated that the world smelled nearly the same to the women without apparent olfactory bulbs as it did to those with them, though the two women's olfactory fingerprints were more similar to each other's than to anyone else's. "It's important to note that their [sense of] smell was not quite normal," says John McGann, a neuroscientist at Rutgers University in Piscataway, N.J., who was not involved in the study. Both of the women had difficulty detecting low concentrations of a roselike smell, one of the most common odors in olfactory testing, he says. "But there's no question [they] could smell." When the team looked in a public database of 1,113 brain scans for other individuals who appeared to be missing olfactory bulbs but still had a sense of smell, it found three other women who matched that description. Like the original pair, one of those women was left-handed. Those results imply that about roughly 0.6 percent of women globally and 4.25 percent of left-handed women lack visible olfactory bulbs but can still smell almost normally, the team says. No men in the database appeared to be missing the structures. "We don't know how to explain how these women can smell, why it's primarily women or why it's more pronounced in left-handed individuals," Sobel says. Human brains are adaptable, so the women's brains could have compensated for a lack of olfactory bulbs early in development (SN: 4/10/14). Or the findings could imply that the current understanding of how people smell is wrong, Sobel says. The researchers are now recruiting more people who appear to lack these structures to test the limit of their scent abilities. Such work could help scientists better sniff out the role of olfactory bulbs in human smelling, and may lead to treatments to help people with anosmia regain the ability to smell. Questions or comments on this article? E-mail us at feedback@sciencenews.org

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