For decades, scientists working with astronauts have known that spaceflight has an effect on neurological systems, said Mill Reschke, chief scientist for NASA Neuroscience. Scientists also have believed the changes we observe in spatial orientation, balance and disturbances in the control of eye movements needed to maintain clear vision when the head is moved must be the result of structural changes in the brain."

Dr. Seidler is making a major step forward with her investigation of changes in the brain acquired during flight, and relating these changes to functional performance following flight," saidReschke.

Seidler and other researchers studied the structural MRIs of 12 astronauts who spent two weeks as shuttle crew members. They also studied the MRIs of 14 astronauts who spent six months on the International Space Station (ISS). Every one of the astronauts experienced increases and decreases in gray matter in the different areas of their brains. The changes were clearer and more pronounced in the astronauts who stayed in space for a longer period of time.

Seidler and colleagues examined structural MRIs in 12 astronauts who spent two weeks as shuttle crew members, and 14 who spent six months on the International Space Station. All experienced increases and decreases in gray matter in different parts of the brain, with more pronounced changes the longer the astronauts spent in space.

"We found large regions of gray matter volume decreases, which could be related to redistribution of cerebrospinal fluid in space," Seidler said. "Gravity is not available to pull fluids down in the body, resulting in so-called puffy face in space. This may result in a shift of brain position or compression."

"It's interesting because even if you love something you won't practice more than an hour a day," Seidler said. But the brain changes researchers observed were equivalent to someone practicing a new skill round-the-clock.

This figure shows dose response effects blue areas are where there are more gray matter decreases in international space station astronauts than in those that just spent a few weeks on the space shuttle.The researchers also found increases in gray matter volume in regions that control leg movement and process sensory information from legs, which may reflect changes related to the brain learning how to move in microgravity. These changes were greater in space station astronauts because their brains were learning and adapting 24/7.

The top row shows brain changes with long duration bed rest; the bottom row shows brain changes with spaceflight. Orange shows regions of increase; blue = decrease. There is some overlap but also notable differences with spaceflight showing more changes in the cerebellum, a structure that is involved in motor learning."In space, it's an extreme example of neuroplasticity in the brain because you're in a microgravity environment 24 hours a day," Seidler said.

Though they haven't pinpointed the exact nature of the changes yet, the findings may lead to new ways of thinking about certain health conditionsfor example, people on long-duration bed rest or people who have normal pressure hydrocephalus, a condition in which cerebrospinal spinal fluid accumulates in ventricles in the brain and causes pressure.

Seidler said the brain changes could reflect new connections between neurons, and she's leading another long-term study that will help determine the repercussions on cognition and physical performance, as well as how long the brain changes last. For example, even after balance returns, the brain might still recruit different pathways to compensate for the structural brain changes caused by spaceflight.

"The behavior may return to normal, but the way the brain controls the behavior may change," she said.

Scott Kelly etched his spot in the record books this fall. In October, he recorded his 382nd day in spacethe most among any American astronaut. But his latest stint in a weightless environment will end in March when Kelly wraps up his mission aboard the International Space Station. Then comes the transition period when Kelly has to re-adapt to Earths gravity. Its during this transition period when many astronauts struggle with depth perception, memory and motor control.

There is no up or down in space, said Seidler. So when astronauts return to Earth, it takes some time for them to adapt because the way their brain interpreted the signals in space is no longer relevant for our gravitational environment. They need time to re-adapt before they can drive a car or maintain their balance well. They need, in some cases, a couple of weeks or a month to recover.

"The brain itself is very fascinating. Its one of our last great scientific frontiers," concludes Seidler.

Dr. Seidler provides new insights about the adaptability of the healthy brain, especially as it involves the complex interplay among perception, cognition, and motor function, said U-M School of Kinesiology Dean Ron Zernicke. Microgravity is a unique means to discover new knowledge about brain function.

Seidler will continuously monitor the brain structure and function of astronauts aboard the International Space Station, with a goal to wrap up her data collection by 2018.

This is a study that takes a lot of patience because there arent a lot of astronauts aboard the International Space Station that we can recruit from, she said. But regardless of the timeline, this type of research has major implications on the health and wellbeing of our astronauts. The brain itself is very fascinating. Its one of our last great scientific frontiers.

The Daily Galaxy via University of Michigan and NASA

Image credit: Top of page With Thanks to neuroscapelab.com,gazzaleylab.ucsf.edu | sccn.ucsd.edu

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