Unlike other mammals, humans don’t make new olfactory neurons, a study suggests
People may be born with all the smell-sensing brain cells they will ever have, a new study concludes.
That makes human brains different from those of rodents, nonhuman primates and other mammals, which constantly make new nerve cells, or neurons, in the odor-processing olfactory bulb. Humans don’t rely on the sense of smell as much as other animals do, so maybe it isn’t surprising that people don’t make new odor-sensing cells, says study author Jonas Frisén, a neuroscientist at the Karolinska Institute in Stockholm.
Neurons are born in two areas: a memory-and-learning center called the hippocampus and the subventricular zone, which surrounds the two vacant spaces in the middle of the brain. In mice, neurons from the subventricular zone migrate to the olfactory bulb and wire into neural circuits, helping the animals learn new smells.
Some evidence exists already that humans also repopulate their hippocampus with new neurons, but data