Research from Karolinska Institutet shows that the human olfactory bulb – a structure in the brain that processes sensory input from the nose – differs from that of other mammals in that no new neurons are formed in this area after birth. The discovery, which is published in the scientific journal Neuron, is based on the age-determination of the cells using the carbon-14 method, and might explain why the human sense of smell is normally much worse than that of other animals.
“I’ve never been so astonished by a scientific discovery,” says lead investigator Jonas Frisén, Tobias Foundation Professor of stem cell research at Karolinska Institutet. “What you would normally expect is for humans to be like other animals, particularly apes, in this respect.”
It was long thought that all brain neurons were formed up to the time of birth, after which production stopped. A paradigm shift occurred when scientists found that nerve cells were...