ESA’s Brain-DTI experiment studies how space reshapes astronauts’ brains, with Sophie Adenot

The European Space Agency (ESA) published on Thursday, October 29 a photo of astronaut Sophie Adenot being prepared for a magnetic resonance imaging scan as part of the Brain-DTI experiment. The details that follow come from ESA’s official article “Brain-DTI: How space reshapes astronauts’ brains”. The experiment examines how the brain adapts to life in microgravity and how it recovers when astronauts return to Earth. Adenot took part in it during the epsilon mission to the International Space Station.

Timing is critical. The brain begins to readapt to Earth’s gravity almost immediately after landing, so post-flight imaging has to be done as quickly as possible. ESA said three MRI sessions were carried out at the :envihab facility of the German Aerospace Center (DLR), next to the European Astronaut Centre in Cologne, within the first two weeks of Adenot’s return from a 237-day mission. A final scan is planned six months after her return, to show how long full neurological recovery takes after such a long stay in space.

The repeated measurements will let researchers determine whether the brain’s readaptation follows a linear, exponential or more complex course. As principal investigator Prof. Floris Wuyts of the University of Antwerp noted: “Eight months in space have a profound effect on the human body and a full return to the pre-flight state takes time.”

Three imaging techniques

Brain-DTI combines several MRI techniques. Diffusion tensor imaging (DTI) tracks the movement of water molecules in brain tissue, mapping nerve pathways and detecting changes in white matter. Resting-state functional MRI (rs-fMRI) shows how brain regions communicate with each other by measuring the blood-oxygenation-dependent signal. Standard anatomical scans measure how much the brain shifts within the skull, how much the ventricles swell and how cerebrospinal fluid is redistributed because of the fluid shift caused by microgravity. Together they give a picture of neuroplasticity, the brain’s ability to reorganise in a new environment.

The fluid redistribution data also feed the study of spaceflight-associated neuro-ocular syndrome (SANS), a condition observed in some astronauts that can affect vision on long missions. It is thought to be linked to increased pressure in the fluid around the brain and spinal cord, which can lead to flattening of the eyeball. Brain-DTI researchers want to explore the connection between the two phenomena.

The largest brain-imaging database in human spaceflight

Since the first scans in 2013, Brain-DTI has grown into the largest neuroimaging dataset in the history of crewed spaceflight. “Since 2013 we have collected brain scans from about 50 astronauts and cosmonauts,” said Wuyts, adding that the findings already help people with dizziness and vertigo-related disorders. He stressed that the entire Crew-12 and the whole of Expedition 75 took part, and that the participation of more women astronauts matters, because it is not known how large sex differences are, if any.

The Brain-DTI team consists of specialists from Belgium, Germany, Italy, Russia and other countries. The experiment is supported by the Belgian BELSPO-Prodex programme and ESA.