Brain Health,

#185: Brains in Orbit with Dr. Rachael Seidler

June 16, 2017

Space:  the Final Frontier.

But what exactly happens to us when we say hasta la vista to Mother Earth?

Microgravity causes a range of cognitive and physiological effects on the human brain and body.  Dr. Rachael Seidler, Professor at the University of Michigan, has been working with NASA to understand these effects.

The Effects of Microgravity

On Earth, gravity is constantly pulling fluids in our bodies down.  To combat this, we have many one-way valves in our bodies that keep the blood pumping up towards our head.

In space, without the force of gravity, fluids in our bodies redistribute, with more fluid in our upper bodies and heads.  That’s why many astronauts have puffy faces in photos taken in space.

Of course, without gravity, bone density and muscle strength also begin to decay.

But not all the changes are due to the physical effects of microgravity on the body.  Astronauts experience a host of cognitive changes, from difficulty focusing upon returning to Earth to loss of balance.

Space also affects mood. At the beginning of a mission, mood is high.  Astronauts are excited to be putting their training to work.

But then mood begins to deteriorate, reaching a low in the third quarter of the mission.  Interestingly, this seems to be independent of length of mission.  Mood rebounds in the final quarter as astronauts prepare to be reunited with loved ones on Earth.

Studying Space on Land

It’s hard to properly study the effects of space on astronauts — there’s no MRI scanner on the International Space Station, after all.  But NASA has found some ways to recreate some of the effects of space right here on Earth.

One such way is to study volunteers placed on bed rest for 70 days with their head tilted 6 degrees below their feet.  The volunteers are supine for the whole 70 days, even using bedpans.  This unpleasant experience mimics many aspects of microgravity, including the shift of fluid towards the head.

The physiological changes observed are similar to those caused by space travel.  Balance is disrupted, along with functional mobility (think navigating an obstacle course) and physical strength.

Not all of these changes come from physical weakness and lack of exercise.  The vestibular system — our inner ear — which integrates sensory information to create balance, is affected.

Building Space Aptitude

Some people adapt to microgravity better than others.  Those who adapt best, face a larger struggle to adapt back to being on Earth.

Dr. Seidler hopes to discover the key to determining who will adapt and to what degree, so as to make the transitions easier on astronauts.

One (partial) key is exercise.  Astronauts work out two hours a day in space, which protects their bone density and muscle mass.  Interestingly, it doesn’t protect balance, which is ruled by the vestibular system.

Looking forward, Dr. Seidler hopes to discover the equivalent of exercise for the vestibular system, so astronauts can protect their balance while in space.

Read Full Transcript

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to top