(Newswire.net — November 11, 2019) — Scientists say they have discovered a biological anomaly that could change everything we know about the sense of smell.
A study published in the Neuron journal shows that some people have a regular sense of smell, despite missing a part of the brain that is thought to be crucial for the sense of smell – sniffing bulbs.
The lack of these bulbs should cause anosmia (a person’s inability to smell), however, the brain seems to find its way to compensate.
Scientists say that scents enter the nose and stimulate nerve endings.
How do we sense smell? A signal that travels to a specialized part of the brain – the olfactory receptors which process signals coming from the nose to identify what we are sniffing at.
A major breakthrough, however, came when researchers at the Weitzman Institute of Science in Israel discovered that there are people who have a common sense of smell even though they don’t have those bulbs.
Scientists came up with the first example when examining the brains of people with a healthy sense of smell, as part of a completely unrelated study.
“We could not find any sign of olfactory bulbs in her brain, it’s an anomaly – this does not make sense, right?” Professor Noam Sobel tells the BBC. Prof Sobel said he had “absolutely no clue” why gender and left-handedness seem to be involved, BBC reports.
The team looked into a public library that had 1,113 brain scans – the Human Connectome Project – and found more examples.
The phenomenon has never been detected in men, but is present in more than four percent of left-handed women.
There are a few ideas, but only new research can determine the actual cause.
One option is for women to have scented bulbs, but they are so small that they cannot be seen on some scanners.
However, this does not explain how they retain such a good sense of smell with such imperceptible bulbs.
Another explanation is the ability of the brain to adapt, known as plasticity. If a baby is born without olfactory bulbs, there is a possibility that another part of the brain can take responsibility for the sense of smell.
But researchers have come up with a more controversial explanation about understanding the sense of smell.
They argue that scent bulbs may not participate as much in odor recognition and instead play a different role, potentially for odor localization instead of identification.
“It’s a big difference,” Professor Sobel said. The fact that their olfactory ability is virtually identical to that of normal subjects is very surprising,” Prof Matthew Cobb of the University of Manchester told the BBC.
The author of the upcoming book titled The Sense of Smell: A Very Short Introduction says that the brain is very flexible and can make up for the lack of scent bulbs.
“For example, there is a man in Marseille whose cortex – the region of the brain generally thought to be involved in higher intellectual functions – is compressed into a tiny sliver of cells, yet he is of average intelligence and holds down a job as a civil servant.
“In China, a young woman has no cerebellum – the structure at the base of the brain involved in co-ordination – and although she does have slurred speech and poor coordination, these symptoms are nowhere near as serious as animal studies would suggest they should be,” Profesor Cobb said.