HomeScienceAstronauts’ brains shift back, forward, and rotate inside skull during spaceflight, study finds

Astronauts’ brains shift back, forward, and rotate inside skull during spaceflight, study finds

A new study reveals spaceflight physically shifts astronauts’ brains inside the skull, with changes lasting months after return, raising new questions about microgravity’s hidden effects on human health.

January 16, 2026 / 13:15 IST
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Astronaut Brains Move Backward, Upward, and Rotate (Image: Canva)
Astronaut Brains Move Backward, Upward, and Rotate (Image: Canva)
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A study led by MIT researchers found that prolonged spaceflight causes the human brain to shift position inside the skull due to microgravity. Using MRI scans of astronauts and comparison groups, scientists observed lasting changes linked to balance issues after return, highlighting the long-term neurological effects of time spent in space.

Spaceflight does more than change how astronauts see Earth, a new study reports, showing that time spent in microgravity physically shifts the brain’s position inside the skull, with effects lasting months after return.

What happens to the brain in microgravity
Researchers examined how extended space missions affect brain anatomy. The study was led by Rachel Seidler at MIT. It was published on 12 January. Scientists analysed MRI scans from astronauts and control participants. The team compared 26 astronauts with 24 non-astronaut participants. The focus was physiological changes, not psychological experiences. Researchers studied how microgravity alters brain positioning.

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MRI scans showed consistent movement patterns after spaceflight. The brain shifted backward and upward inside the skull. It also rotated upward following time in space. Some changes remained months after Earth return. Scientists have long tracked spaceflight effects on bodies. Brain anatomy responses remain less clearly understood. This study aimed to close that knowledge gap.

What the study found across missions
Fifteen astronauts provided scans before and after missions. Another eleven astronauts contributed additional MRI data. Researchers also studied a bed rest experiment group. Bed rest simulated microgravity using head down tilt. The team divided the brain into 130 regions. Each region was analysed independently for displacement. Results showed widespread movement across many brain areas.