An international team of scientists found that prolonged exposure to microgravity affects brain function, and the recovery period can last about a year. This was announced in a press release on EurekAlert !.
The specialists examined 10 cosmonauts who spent an average of 189 days on board the International Space Station (ISS). The participants in the experiment underwent magnetic resonance imaging before flying to the ISS, immediately after returning to Earth and seven months after the completion of the mission.
It turned out that in the returned astronauts, the volume of gray matter, consisting of the bodies of neurons, had decreased since the first scan. After seven months, this figure did not have time to return. In addition, prolonged exposure to microgravity increased the content of cerebrospinal fluid in the ventricles of the brain, as well as in the subarachnoid space. This influx reduces the volume occupied by the white matter (consisting of bundles of axons), which is observed even months after returning from the ISS.
Scientists emphasize that at the moment it is not clear whether these changes affect the cognitive abilities of the ISS crew members. However, it is known that with a long stay in zero gravity, visual acuity decreases. This may be due to an increase in the pressure exerted by the cerebrospinal fluid on the retina and optic nerve.