Multiple Spaceflights Linked to Altered Brain Structure

A recent research published in Scientific Reports reveals that spaceflight experiences, especially longer missions and shorter breaks between missions, can cause changes in the fluid levels in the brain. These changes might not go back to normal before the next spaceflight. The study found that the ventricles, which are spaces in the brain filled with cerebrospinal fluid, expand more as the length of space missions increases, especially up to six months. Additionally, if there is less than a three-year gap between missions, it may not be enough time for the ventricles to fully recover (1^✔ ✔Trusted Source
Impacts of spaceflight experience on human brain structure

Go to source). Spaceflight induces widespread changes in the human brain including ventricle volume expansion, but it is unclear if these changes differ with varying mission duration or number of previous spaceflight missions. Rachael Seidler and colleagues scanned the brains of 30 astronauts using MRI, pre- and post-spaceflight, including those on two-week missions (eight astronauts), six-month missions (18 astronauts) and longer (four astronauts). They found that longer spaceflight missions resulted in greater ventricular enlargement, which tapered off after six months in space.

Astronauts May Need More Than 3 Years Between Spaceflights

The authors found that for 11 astronauts who had more than three years to recover in between missions, there was an associated increase in ventricle volume after their most recent mission. However, the authors found that in seven astronauts who had a shorter recovery time in between missions there was little to no enlargement of the ventricles post-flight compared to pre-flight. They propose that less than three years between spaceflights may not be enough time to allow ventricles to recover their compensatory capacity to accommodate the increase in intracranial fluid and they remain enlarged when the astronauts return to space within this time frame.

As spaceflight becomes more frequent and of longer duration, the findings provide insight into how spaceflight experience, both previous and current, may influence brain changes. The authors conclude that their findings can help to improve guidance for future mission planning.

Reference:

1. Impacts of spaceflight experience on human brain structure - (https://www.nature.com/articles/s41598-023-33331-8)

Source-Eurekalert