This is Scientific Americans 60 Second Science.

I'm Karen Hopkins.

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Time spent in 0G changes the body.

Astronauts come home with bone loss and muscle weakness.

But what happens in their heads?

To find out, researchers examine MRIs of astronauts' brains taken before and after flight.

They looked at 12 astronauts who spent two weeks on the shuttle crew and 14 who spent

half a year on the International Space Station.

What they saw is that the spacefarer's gray matter appeared compressed, particularly around

the front and sides of the brain and the areas around the eyes.

That's probably due to a redistribution of cerebral spinal fluid, which is no longer being pulled down by gravity,

the researchers say. The exception to this

compression is in a small area of the brain that controls the feeling in and the

movement of the legs. In this region, expanded in the astronauts, particularly the

ones who spent six months circling the Earth.

That change, the researchers say, could reflect the formation of new neural connections,

as the brain tries to adapt to the weightless conditions.

This study is in the Nature Partner Journal, Microgravity.

The findings could have applications back here on Terra Firma. For example, we could learn more

about treating the brain changes that take place in people who were on extended bed rest,

with their feet elevated and thus higher than their heads.

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