The long periods experienced in a microgravity environment cause the brain to reorganize itself inside the cranial box – this was the conclusion of the newest stage in the work of a team of researchers from Belgium, Russia and Germany who, since 2014, have been studying the effects of long missions in space in brain tissues.
According to the work published in the journal Science Advances, eleven cosmonauts participating in long-term missions (on average, 171 days) at the International Space Station (ISS) underwent hundreds of brain scans between February 2014 and March 2019, both before the launch as early as 9 days after the return. Eight were still examined 7 months later to see if the perceived changes were gone.
The scans revealed that the brain, in long periods of microgravity, migrates inside the cranial box; cerebrospinal fluid (or CSF, a saline solution low in proteins and cells, which acts as a buffer for the cerebral cortex and spinal cord), in turn, increases in volume, eventually accumulating around the eyes (which causes vision damage, but reversibly).
The reorientation of the brain gave rise to new motor skills, in addition to finer balance and coordination. The cosmonauts’ brain returned to its normal position after 7 months on Earth.
Normality or dementia
In a study published in 2019, the same researchers found that the increase in CSF volume also caused brain ventricles (a system of 4 interconnected cavities) to increase by an average of 11.6%.
After 7 months, all cosmonauts had brain ventricles 6.4% larger, on average, than before they were exposed to microgravity.
It is not yet known what the long-term effects on the brain are in space. During the follow-up, no symptoms of so-called normal pressure hydrocephalus were detected (the ventricles also increase, causing difficulty in walking, bladder problems and dementia). There is no data after the observation period.