When space travellers experience weightlessness, their brain changes in order to adapt to this. A new study has examined how these changes take place in astronauts who have been in space for six months, and found that the changes linger even eight months after their return to Earth.
The study, which looks at how the brain's organisation is changed after a six-month mission to the International Space Station (ISS), was carried out by scientists of the University of Antwerp and University of Liège. It has been published in the journal Nature Communications Biology.
Our brains account for the laws of gravity in our existing environment. For example, a child learns that he or she should not drop a glass on the floor. Space travellers, on the other hand, stay in a weightless environment, where what the brain understands about gravity no longer holds. This forces the brain to adapt.
The study took MRI data from the brains of 14 astronauts, before and times after they travelled to space. They collected the data in a resting condition, when the astronauts were not engaged in a specific task (the brain was in its default state).
An analysis of the brain’s activity at rest revealed the changes. The scientists looked at “functional connectivity”, which indicates how activity in some brain areas is correlated with activity in other areas. Their analysis showed changes in functional connectivity in specific regions.
“We found that connectivity was altered after spaceflight in regions which support the integration of different types of information, rather than dealing with only one type each time, such as visual, auditory, or movement information,” a press release from the University of Liège quoted researchers Steven Jillings and Floris Wuyts as saying.
Some of these altered communication patterns remained for eight months after the astronauts returned to Earth. Some other patterns that had changed, however, returned to the state they had been in before the space mission.”
According to the scientists, if a change in brain communication is retained, it may indicate a learning effect. If a change is transient, it may indicate more acute adaptation to changed gravity levels.
Raphaël Liégeois, Doctor of Engineering Science (ULiège) with a thesis in the field of neuroscience, is future astronaut with the European Space Agency. The press release quoted him as saying: “Understanding physiological and behavioural changes triggered by weightlessness is key to plan human space exploration. Therefore, mapping changes of brain function using neuroimaging techniques as done in this work is an important step to prepare the new generation of astronauts for longer missions.”