Discovery Roundup: The Brain

By Kylie Wolfe

In our first Discovery Roundup, you'll find four interesting stories about the brain. Keep reading to learn about the brains of marathon runners and astronauts, plus the science behind fainting, and more.

Marathons and Myelin

When athletes run marathons, their bodies push through pain and pull energy from every part of the body, all to endure and succeed. A new study posted at bioRxiv.org suggests that runners may even be expending brain energy, using myelin—the tissue that insulates neurons—as another source of fuel.

Brain scans showed that runners have less myelin following a long-distance race than before one. But after two weeks, their supply of myelin recovers to about pre-race levels. This supports the concept of myelin plasticity, the idea that this protective layer can shift in size and quantity to meet the body’s needs.

Eavesdropping Electrodes

When you listen to music, your brain decodes all of the lyrics, rhythms, and harmonies, and that interpretation results in distinct neural signals. A study published in PLOS Biology used electrode implants to record this type of brain activity in 29 people. Then, using a computer model, the team recreated sounds that were similar to a song participants had listened to.

Through this experiment, researchers were also able to determine what areas of the brain reacted to certain aspects of the music. These findings, and the ability to translate the brain’s electrical signals into sound, could someday help improve communication devices for people with disabilities.

Feeling Faint

Fainting isn’t always caused by an underlying medical issue. Sometimes the sight of blood or experiencing an extreme emotion can cause a person to faint. And there’s no other meaning behind it—except that researchers can now offer a scientific explanation.

A study published in Nature revealed that a pathway connecting the heart’s ventricles to an area of the brainstem helps the body and mind coordinate heart rate, blood pressure, and breathing. When that pathway was stimulated in mice, their heart rates dropped quickly, and they fainted. These findings increase our understanding of fainting and the potential for better treatments.

Astronaut Anatomy

Space travel is a dream come true for astronauts, but it also takes a toll on the human body. A recent study in Scientific Reports found that a trip to space causes the brain’s ventricles to expand and collect additional fluid in response to lower gravity. And once the mission is complete, these structures don’t recover quickly.

Researchers took MRI scans of 30 astronauts before and after their space missions and found that longer missions result in more swelling. Astronauts who had been to space within the last three years didn’t experience much swelling because their ventricles hadn’t returned to their original sizes yet, but those who hadn’t been to space in three or more years came back with ventricles 10 to 25 percent larger. This suggests that astronauts may need to space out their space travel to help ensure their health and safety.