The researchers had examined ten Russian cosmonauts - before their flight, immediately afterwards, and again months later, to travel to space. Now they present their results: Longer stays in space therefore do not change the brain of spacers, not just in the short term, as the international team reported in the "New England Journal of Medicine".
Even half a year after the return of the spacemen of long-term missions in space, there would still be "large volume changes", it is said by the Ludwig Maximilian University (LMU) in Munich. Researchers from there were involved in the study. There are, so the doctors report, evidence that the effects on the brain are greater, the longer people are in space.
The researchers observed in the spacers about seven months after their return to Earth, a lesser volume of the so-called gray matter. This is the part of the cerebrum that mainly contains nerve cells. This effect regressed somewhat over the course of half a year after landing - but not completely.
Magnetic Resonance Imaging (MRI) scans also showed that the space in the cerebrum was filled with nerve fluid called CSF. And also on the white matter, which is the part of the brain tissue, which consists mainly of nerve fibers, changes were observed: Immediately after the landing, it did not look like it, but then it was half a year compared to the previous investigations shrunk.
Whether the changes are relevant to the minds of astronauts, is still unclear, according to researchers. According to the information provided so far only changes in the eyesight, which - so the researchers suspect - by the pressure of the extended Nervenwassers on the retina and the optic nerve could have originated.
Between 2014 and 2018, the researchers studied ten Russian astronauts who spent an average of 189 days on the International Space Station. Scans were made before departure and after returning to Earth; at seven of the cosmonauts around half a year later again.
"We are the first to be able to study changes for a long time after landing," said Peter zu Eulenburg, one of the researchers involved. To minimize the risks of long-term missions, additional and longer-term studies are essential.
The fact that longer stays in space can change the brain structure of astronauts had already been shown in previous studies. This included a project by the US Space Agency Nasa, in which the University Hospital Frankfurt was involved.
The researchers had observed that astronauts returning from the ISS reported frequent visual disturbances and headaches. The scientists discovered a narrowing of the central furrow in the astronaut's brain, and the brain had shifted upwards.