Study Finds Astronauts' Brains Shift in Space, Effects Linger After Return

Research reveals complex brain deformations in microgravity, with implications for long-term space missions.

Apr. 11, 2026 at 2:12am

Got story updates? Submit your updates here. ›

A highly structured abstract painting in soft blues, greens, and grays, featuring sweeping geometric arcs, concentric circles, and precise botanical spirals, conceptually representing the deformations and shifts of the human brain in the absence of gravity.An abstract visualization of the complex structural changes astronauts' brains undergo in the microgravity of space, with lasting effects even after returning to Earth.Gainesville Today

A groundbreaking study published in the Proceedings of the National Academy of Sciences has found that astronauts' brains undergo significant shifts and deformations while in microgravity, with some effects persisting for months after returning to Earth. The research team, led by scientists at the University of Florida, analyzed MRI data from 26 astronauts and 24 participants in a long-duration bed rest experiment, revealing complex changes in brain structure and function that varied across different regions.

Why it matters

These findings have major implications for the future of space exploration, as they suggest that the effects of microgravity on the brain are not limited to temporary fluid shifts. The structural changes observed could help explain common post-spaceflight symptoms like space motion sickness, dizziness, fatigue, and balance problems, some of which can linger for months. Understanding these brain shifts will be essential for developing countermeasures to protect astronaut health as missions grow longer, including potential trips to the Moon and Mars.

The details

The study found that the brain moves upward and backward within the skull in microgravity, with the degree of shift correlating to the duration of the spaceflight. The largest displacement, about 2.5 millimeters, was observed in the supplementary motor cortex, a region involved in planning and coordinating movement. The researchers also discovered a link between brain movement and physical performance, with larger shifts in a multisensory brain region associated with greater declines in balance after astronauts returned to Earth.

  • The study was published in the Proceedings of the National Academy of Sciences in April 2026.
  • The research team analyzed MRI data from 26 astronauts and 24 participants in a long-duration bed rest experiment.

The players

Tianyi Wang

A researcher at the University of Florida and a co-author of the study.

Dr. Rachael Seidler

A professor at the University of Florida and the lead author of the study.

Dr. Eran Shankar

An Israeli space medicine physician who commented on the study's findings.

Got photos? Submit your photos here. ›

What they’re saying

“These findings reinforce concerns that the effects of microgravity on the brain are not limited to temporary fluid shifts. These changes could help explain symptoms including space motion sickness, dizziness, fatigue, and balance problems, some of which can persist for months after astronauts return.”

— Dr. Eran Shankar, Israeli space medicine physician

What’s next

The researchers emphasize that more research is needed to determine whether different gravity environments, like the Moon or Mars, could alter recovery time or long-term outcomes. Understanding these brain shifts will be essential for developing countermeasures to protect astronaut health as missions grow longer.

The takeaway

This study highlights the complex and long-lasting effects of microgravity on the human brain, which could have significant implications for the future of space exploration. As missions to the Moon, Mars, and beyond become more ambitious, protecting astronaut health and well-being will be crucial, and this research provides important insights that can help guide the development of effective countermeasures.