Evolution and humans: brain plasticity: no olfactory bulbs (Evolution)

by David Turell , Thursday, November 07, 2019, 23:47 (1841 days ago) @ David Turell

Primarily in left- handed women. They have good senses of smell:

https://www.smithsonianmag.com/smart-news/olfactory-bulb-might-not-be-necessary-smell-s...

"But a new paper published in the journal Neuron has scientists questioning what the nose knows. Researchers have identified two women without olfactory bulbs that were still able to smell just as well, or better, than the average person.

"The finding happened by chance. Researchers at the Weizmann Institute of Science in Israel were conducting MRI scans of people with a good sense of smell. So the study team was shocked when they looked at the brain scan of one participant and found the 29-year-old, left-handed woman did not appear to have an olfactory bulb.

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"Finding two women without olfactory bulbs, but with a sense of smell seemed like too much of a coincidence, so the team did a deep dive into the data, analyzing MRI brain scans from the Human Connectome Project, which has published over 1,113 brain scans. From that data set, which includes 606 women, they found three more female subjects who did not have olfactory bulbs, but retained their sense of smell. One of those women was also left-handed. According to the data, the team estimates that about 0.6 percent of women globally and 4.25 percent of left-handed women lack an olfactory bulb but still retain a sense of smell. None of the men in the database appeared to have the same ability.

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"How exactly the women are able to smell without their sense organ is not known. “I’m not sure that our textbook view of how the [olfactory] system works is right,” Sobel tells Sofie Bates at Science News.

"The team does have a theory about how the smelling works. It’s thought that scents are mapped onto the olfactory bulb, with certain areas corresponding to certain smells. But it’s possible that in these cases, scents are mapped on a different area of the brain."

Comment: This is simply the brain's amazing ability at plasticity.