Nose-breathing boosts memory, study finds

Nasal inhalation may help us retain olfactory memories longer.

  • A new study confirms a suspected connection between the nose and memory.
  • Twenty-four subjects memorized 12 smells delivered through a nasal cannula during two training sessions.
  • The results of the experiments suggest we can consolidate memories by breathing through our nose.

Scientists have been intrigued for some time about the effect that breathing has on the brain, and Big Think has discussed this before. Now, a new study, published this month in The Journal of Neuroscience, nails down the link between breathing through one's nose — as opposed to one's mouth — and the robust storage of memories.

"The idea that breathing affects our behaviour is actually not new. In fact, the knowledge has been around for thousands of years in such areas as meditation," said Artin Arshamian, the lead author of the study, which took place at Sweden's Karolinska Institutet. "But no one has managed to prove scientifically what actually goes on in the brain. We now have tools that can reveal new clinical knowledge."

How the study tested the effect of nose-breathing on memory

Nasal cannula. Photo credit: S. Bonaime/Shutterstock

One stumbling block to understanding how breathing through the nose affects the brain is that scientists' typical subjects — mice and rats — don't breathe through their nose. Therefore, sniffing out the truth of the matter requires human subjects. And, appropriately enough, the experiments involved smells.

The study's 24 subjects memorized 12 smells delivered through a nasal cannula during two training sessions. Afterward, they were given an hour off during which they were instructed to breathe exclusively through either their mouths or noses.

This was followed by exposure to a variety of scents, some of which were from their training sessions and some of which were new. Subjects were asked to differentiate between the two.

What the scientists found was that those who'd breathed through their noses during their hour off were more likely to recognize the scents from training sessions, suggesting that their nose-breathing had more effectively stored what they'd learned.

Next steps

Easier research implicated receptors in the olfactory bulb that can detect both scents and variations in airflow. Scientists have also seen different areas of the brain exhibit activity during inhaling and exhaling, but how this all ties together is as of yet unknown.

Arshamain tells KI News:

"The next step is to measure what actually happens in the brain during breathing and how this is linked to memory. This was previously a practical impossibility as electrodes had to be inserted directly into the brain. We've managed to get round this problem and now we're developing, with my colleague Johan Lundström, a new means of measuring activity in the olfactory bulb and brain without having to insert electrodes."

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Scientists study tattooed corpses, find pigment in lymph nodes

It turns out, that tattoo ink can travel throughout your body and settle in lymph nodes.

17th August 1973: An American tattoo artist working on a client's shoulder. (Photo by F. Roy Kemp/BIPs/Getty Images)
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In the slightly macabre experiment to find out where tattoo ink travels to in the body, French and German researchers recently used synchrotron X-ray fluorescence in four "inked" human cadavers — as well as one without. The results of their 2017 study? Some of the tattoo ink apparently settled in lymph nodes.


Image from the study.

As the authors explain in the study — they hail from Ludwig Maximilian University of Munich, the European Synchrotron Radiation Facility, and the German Federal Institute for Risk Assessment — it would have been unethical to test this on live animals since those creatures would not be able to give permission to be tattooed.

Because of the prevalence of tattoos these days, the researchers wanted to find out if the ink could be harmful in some way.

"The increasing prevalence of tattoos provoked safety concerns with respect to particle distribution and effects inside the human body," they write.

It works like this: Since lymph nodes filter lymph, which is the fluid that carries white blood cells throughout the body in an effort to fight infections that are encountered, that is where some of the ink particles collect.

Image by authors of the study.

Titanium dioxide appears to be the thing that travels. It's a white tattoo ink pigment that's mixed with other colors all the time to control shades.

The study's authors will keep working on this in the meantime.

“In future experiments we will also look into the pigment and heavy metal burden of other, more distant internal organs and tissues in order to track any possible bio-distribution of tattoo ink ingredients throughout the body. The outcome of these investigations not only will be helpful in the assessment of the health risks associated with tattooing but also in the judgment of other exposures such as, e.g., the entrance of TiO2 nanoparticles present in cosmetics at the site of damaged skin."

Photo by Alina Grubnyak on Unsplash
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