Space flights cause irreversible changes in the human brain

Scientists understand the harmful effects of microgravity on the human body. The harsh environment of space negatively affects the brain, muscles, bones, nervous and reproductive system. But scientists still don’t know all the details. A new study sheds light on a new problem of long-term space flights, which reveals the detrimental effect of microgravity on the fluid in the human brain.

The influence of space on the brain is the most destructive for people. Photo: Unsplash

This cerebrospinal fluid, stored in the brain in four pockets called ventricles, helps soften the brain and keep it protected. It is also associated with the leaching of cellular waste and the supply of nutrients from the bloodstream.

Researchers from the University of Florida, NASA’s Johnson Space Center have found that the increase in the size of ventricles and the volume of brain fluid during space flights depends on certain factors, in particular, on the duration of astronauts’ stay in space and the intervals between their space adventures. Moreover, intervals between flights of less than three years do not give enough time for the ventricles to fully restore their compensatory ability.

An increase in the size of the ventricles and the volume of brain fluid was also observed in previous studies. It is accompanied by an upward displacement of the brain inside the skull in microgravity, which, in turn, contributes to the redistribution of fluid.

Accumulation of fluid in the brain

Using MRI scans of 30 astronauts, the researchers have found that the longer the spaceflight lasts, the more the ventricular size increases. Up to six months, their size is constantly increasing, after which the rate of change is leveled.

It is believed that the swelling of the ventricles of the brain is a compensatory mechanism during space flight, allowing the brain to adapt to changes in the cerebrospinal fluid. After returning to Earth, the brain fluid slowly returns to its normal distribution.

In seven astronauts who had a break between flights of less than three years, ventricular expansion was not so noticeable. The team suggests that this means that the ventricles of the brain do not have time to contract and reboot in order to cope with the increase in the amount of cerebrospinal fluid.

The scans also showed that the more previous missions an astronaut had completed, the less noticeable the increase in ventricular size after the mission. It looks as if the brain of these astronauts was “less fit” due to previous expansions, or had exhausted its ability to cope with the stresses of spaceflight.

Future risks

This study did not consider further health effects due to changes in ventricular size and fluctuations in brain fluid levels. But it is obvious that brain shifts occur, and they are affected by the duration and frequency of flights. Previously, this additional cerebrospinal fluid was associated with vision problems in astronauts.

Due to the fact that longer missions to the Moon and Mars are planned in the coming years, we need to understand as much as possible about what astronauts will go through. And the impact on the brain is the most disastrous for people. These findings illustrate some of the potential irreversible changes in the human brain during long future space flights.

According to Scientific Reports

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