Analysis of brain scans finds increase in white and grey matter in regions involved in physical movement
Brain scans of cosmonauts have revealed the first clear evidence of how the organ adapts to the weird and often sickness-inducing challenge of moving around in space.
Analysis of scans taken from 11 cosmonauts, who spent about six months each in orbit, found increases in white and grey matter in three brain regions that are intimately involved in physical movement.
The changes reflect the “neuroplasticity” of the brain whereby neural tissue, in this case the cells that govern movement or motor activity, reconfigures itself to cope with the fresh demands of life in orbit.
“With the techniques we used, we can clearly see there are microstructural changes in three major areas of the brain that are involved in motor processing,” said Steven Jillings, a neuroscientist at the University of Antwerp in Belgium.
Visitors to the International Space Station face a dramatic shock to the system for a whole host of reasons, but one of the most striking is weightlessness. While the space station and its occupants are firmly in the grip of gravity – they are constantly falling around the planet – the body must recalibrate its senses to cope with the extreme environment.
Images of the cosmonauts’ brains, taken before and after missions lasting on average 171 days, and again seven months later, confirmed that the cerebrospinal fluid that bathes the brain redistributes itself in orbit, pushing the brain up towards the top of the skull. This also expands fluid-filled cavities called ventricles, which may be linked to a loss of sharpness in the cosmonauts’ vision, a condition called spaceflight-associated neuro-ocular syndrome or Sans.
But the scans also picked up microstructural changes in three brain regions, namely the primary motor cortex, which sends movement signals to muscles; the cerebellum, which plays a role in fine movements; and the basal ganglia, an area that helps to initiate movements. Some of the changes were still evident seven months after the cosmonauts returned to Earth.
“What we see makes so much sense. It’s a sign of the complex situation cosmonauts find themselves in, and that they are learning how to adapt to this very extreme environment,” said Floris Wuyts, a senior author on the study published in Science Advances. “One thing that is so much different in space is the lack of gravity. If there’s a lack of gravity you have to re-learn how to move appropriately.”
First-time flyers to the International Space Station not only have to learn how to move around the orbiting outpost – an education that tends to come with bruises – they must also recalibrate their sensory systems. On Earth, the brain learns to understand our place in the world by combining information from our vestibular system with what we see and feel with our other senses. A visitor to the space station has to forget notions of up and down and learn afresh how objects move. Many experience bouts of dizziness and sickness before their brains adapt.
The findings will feed into a project run by the Russian Space Agency, Roscosmos, and the European Space Agency, to understand the impact of spaceflight on the human brain and how to mitigate any unpleasant effects. “This could really be a game-changer for countermeasures that are used,” said Wuyts. “It will have an impact on future missions for space crews, but also for tourists who want to spend a while in space.”
World news – GB – Scans reveal how brain adapts to life in space