Long duration of space travel causes astronaut brain to expand: Study

Space travel of long durations could lead to permanent changes in brain volume of astronauts as well as deformation of the pituitary gland, warns a study.

Published in the journal Radiology, the researchers performed brain MRI on 11 astronauts, including 10 men and one woman, before they traveled to the International Space Station (ISS).

"What we identified that no one has really identified before is that there is a significant increase of volume in the brain`s white matter from preflight to postflight," said study lead author Larry Kramer from the University of Texas Health Science Center at Houston, US.

According to the study, the researchers followed up after the astronauts returned conducting similar tests, and then at several intervals throughout the ensuing year.

The MRI results showed that the long-duration microgravity exposure had caused expansions in combined brain and cerebrospinal fluid (CSF) volumes of the astronauts. A CSF is the fluid that flows in and around the hollow spaces of the brain and spinal cord.

The combined volumes remained elevated even after one year postflight, suggesting permanent alteration.

"White matter expansion in fact is responsible for the largest increase in combined brain and cerebrospinal fluid volumes postflight," Kramer said.

Chronic exposure to elevated intracranial pressure during spaceflight is hypothesized to be a contributing factor.

MRI also showed alterations to the pituitary gland, a pea-sized structure at the base of the skull often referred to as the "master gland" because it governs the function of many other glands in the body.

Most of the astronauts had MRI evidence of pituitary gland deformation suggesting elevated intracranial pressure during spaceflight. "We found that the pituitary gland loses height and is smaller postflight than it was preflight," said Kramer.

More than half of the crew members on the ISS have reported changes to their vision following long-duration exposure to the microgravity of space.