Another study shows how microgravity can affect the human brain, this time showing that astronauts’ brains compress and expand during spaceflight.

MRI scans done on more than 20 astronauts revealed these results in new research from the University of Michigan, with the findings hoped to have applications in treating conditions that affect brain function.

Changing Brain Shape

Principal investigator Rachael Seidler and her colleagues scanned and examined 12 astronauts who were shuttle crew members for two weeks, as well as 14 others who spent six months on board the International Space Station. Comparing the scans, they found out that the volume of gray matter either increased or decreased, with the change depending on the length of time spent out in space.

According to Seidler, the decrease in large regions of gray matter could be linked to redistributed cerebrospinal fluid in space.

“Gravity is not available to pull fluids down in the body, resulting in so-called puffy face in space,” she said in a statement. “This may result in a shift of brain position or compression.”

The team also detected increased volumes of gray matter in brain regions controlling leg movement as well as process movement information in the legs. This aspect may echo brain changes that related to learning about and adapting to microgravity.

They also likened the brain changes to someone practicing a new skill 24/7, pointing to an extreme case of neuroplasticity in the brain since it’s a microgravity setting experienced 24 hours a day.

The nature of the brain changes will still be studied further, but the findings may lead to new methods of addressing certain diseases. They may benefit people on long-term bed rest as well as those with hydrocephalus, where the cerebrospinal fluid collects and exerts pressure in ventricles of the brain.

The next step for the team, which discussed their findings in the journal Nature Microgravity, is to determine how the brain changes last and whether those effects of spaceflight pinpointed are permanent or long-lasting in the body.

Gene Effects Of Spaceflight

NASA is yet to release official results from its unprecedented Twin Study, but early findings on twin brothers Scott and Mark Kelly indicated that space travel dramatically changes human biology, including gene expression.

As twins, the astronaut brothers have almost identical genomes, so the study is observing biological changes brought about by extended stay in microgravity. Scott’s telomeres, those protective caps found on each DNA strand, were found to be longer than his brother’s when he returned recently to Earth. Those telomeres already returned to their normal length prior to the space mission, so scientists are analyzing how spaceflight caused them to elongate.

Spaceflight can take its toll on the human body, as demonstrated by the return to Earth of astronauts such as Tim Peake after days in orbit.

When they land back on Earth, their bodies likely need to readjust to the normal gravity back home. The ISS has about 90 percent of Earth’s normal gravity, but the continuous free-fall of the space laboratory during orbit allows the astronauts onboard to experience the weightlessness.