Researchers looking at the brains of 12 cosmonauts discovered "significant microstructural changes" in the white matter that controls memory.
Within the brain, as well as to and from the rest of the body, communication is essential.
The components of the brain responsible for communication between gray matter and the body, as well as between gray matter regions, are referred to as white matter. In a nutshell, white matter is the brain's communication channel, whereas gray matter is where information is processed.
A team of international researchers led by Dr. Floris Wuyts of the University of Antwerp has been investigating the brains of humans traveling to space as part of a cooperation effort between the European Space Agency and Roscosmos.
The data was gathered using diffusion magnetic resonance imaging (dMRI) scans taken shortly before and after the subjects' time in space, which lasted an average of 172 days. Seven months later, more scans were performed, and while some changes had been reversed, a few remained apparent.
The study discovered modifications in neuronal circuits connected to sensory and motor processes, which they believe may have something to do with the cosmonauts' adaptation to living in microgravity.
"Considering the different physics and kinesthetics applying to the extreme environment of space and the hypothesis that these have significant effects on the brain's representation and control of the body, these tracts are therefore suspected to reflect this altered sensorimotor function shown in space travelers," the team writes.
This is the first time fiber tractography, a type of brain imaging, has been utilized to study the impacts of spaceflight. The method creates a three-dimensional image of neuron tracts, revealing the brain's wiring structure.
While changes in the brains of space travelers have previously been observed, this study was able to get a deeper look at the actual connections between neurons and how they shifted by utilizing fiber tractography.
The researchers initially mistook alterations in the corpus callosum, the primary highway that connects both hemispheres of the brain, for an increase of the brain's ventricles, which are a connected network of chambers filled with fluid that sit next to the corpus callosum.
What we can be certain of is that our bodies attempt to adapt to the harsh environment of space. Previous research has found evidence of an elevated risk of disease and various ways the brain can be affected. It also indicates that spending time in space has various impacts on men and women.
It's very early in the study of this specific brain adaption with this specific scanning technique, but the more we know about human bodies and zero gravity, the better we'll be able to prepare for journeys to other planets.
The research has been published in Frontiers in Neural Circuits.
