By Elton Gomes
Travelling in space could lead to lasting effects on the brain, according to a long-term study involving Russian cosmonauts. Space travel could also lead to muscle atrophy and reduction in bone density.
The research however was unable to elaborate on how different tissues of the brain react to exposure to microgravity, said a researcher from Ludwig Maximilian University of Munich (LMU), Germany, said, as per a report in NewsNation.
It also remains unclear whether and to what extent the observed neuroanatomical changes continue to exist after the astronauts returned to normal gravity.
The brain scans of astronauts revealed significant structural changes as a result of extra-terrestrial journeys. Their brains reportedly shifted upwards and the cerebrospinal fluid (CSF) spaces at the top of the brain were found to be narrowed.
It should be noted that these significant changes were only found in the brains of the astronauts who were able to endure long hours of space travel.
The development comes after a similar study was conducted in 2017 wherein researchers scanned the brains of 34 astronauts before and after they spent time in space. In that study, the brain scans revealed that most astronauts who were part of long-duration space missions had several key changes to their brain’s structure after returning from space.
The present study conducted is a first because it has been possible to objectively quantify changes in brain structures following a space mission also including an extended follow-up period, neurologist professor Peter zu Eulenburg from LMU said, Daily Mail reported.
What does the study indicate
The study was conducted by a team of neuroscientists from the University of Antwerp, Belgium, and the LMU. It showed that differential changes in the three main tissue volumes of the brain were detectable for at least six months after the end of the astronauts last mission.
“Our results point to prolonged changes in the pattern of cerebrospinal fluid circulation over a period of at least seven months following the return to Earth,” Professor Eulenburg said, IANS reported. “However, whether or not the extensive alterations shown in the grey and the white matter lead to any changes in cognition remains unclear at present.”
A total of 10 cosmonauts participated in the study. Each of the 10 had spent an average of 189 days on board the International Space Station.
The magnetic resonance tomography (MRT) scans were performed on the astronauts during the time they were on Earth. The scans revealed that there was a reduction in the volume of grey matter as compared to before the launch.
Effect could be partly reversed
Continuing the experiment, follow-up scans were conducted seven months later, and it was found that the effect was partially reversed but it remained detectable. However, there was an increase in the volume of CSF within the cortex during long-term exposure to microgravity.
This process was also noted in the external spaces that cover the brain after the astronauts returned to Earth. The white matter tissue volume (those parts of the brain that are primarily made up of nerve fibres) appeared to be unchanged.
However, a subsequent examination conducted six months later indicated a widespread reduction in volume relative to both earlier measurements. In this case, the researchers presume that over the course of a longer time frame in space, it is possible that the volume of the white matter could be replaced by an influx of cerebrospinal fluid.
This process could then be slowly reversed when the astronauts returned to Earth, which leads to a reduction in the volume of white matter.
What are the other changes astronauts need to be prepared for
Changes in cerebrospinal fluid have been known to cause other effects as well one of which is blurred vision. Astronauts often complain about blurry vision on their return to Earth. Scientists have blamed the problem on fluids floating up through the body among low-gravity conditions.
Gravity forces Earth-bound bodies to work a surprising amount, even when a person is resting. However, such forces do not function in space this means that astronauts muscles grow measly faster and their bones become more prone to breakage. Astronauts can also lose roughly one to two per cent of their bone mass each month, with the greatest losses in their lower backs and legs.
Elton Gomes is a staff writer at Qrius