Researchers test brain stimulation in zero gravity

“It’s exciting. I love this stuff!” said Bashar Badran, Ph.D. “This is so fun.”

Not many researchers get the chance to float, weightless, 32,000 feet above the Earth. Medical University of South Carolina scientists usually conduct research in labs – controlled settings where they can carefully repeat experiments to double-check results. But with an eye toward what real astronauts might experience in future space travel, a few scientists recently took to the skies to do brain research in zero gravity.

Neuroradiologist Donna Roberts, M.D., and neuroscientist Badran collaborated on the project to conduct transcranial magnetic stimulation, or TMS, on themselves and a group of volunteer assistants, mostly from the Department of Psychiatry and Behavioral Sciences in the MUSC College of Medicine.

Roberts has spent years studying how zero gravity and microgravity affect the human brain – in fact, that was her motivation for going to medical school. This experiment was primarily a test case to show that TMS could be safely used in zero gravity and to compare participants’ results under the force of Earth’s gravity to their results in zero gravity.

During a TMS procedure, a magnetic pulse is sent through the skull into the brain to stimulate electrical activity. The pulse is highly localized – it doesn’t reach the entire brain. The TMS administrator places a coil over the subject’s head; when the subject’s thumb twitches, the administrator knows the TMS coil is in the right spot.

Badran and Roberts sit behind a desk together
Drs. Bashar Badran and Donna Roberts used their diverse expertise to pull off an experiment in zero gravity. Photo by Sarah Pack

Here on Earth, TMS is FDA approved for hard-to-treat depression. Scientists at MUSC and elsewhere are also investigating using TMS for post-traumatic stress disorder; to treat cravings and pain in people under treatment for opioid use disorder; and in physical and mental rehab for stroke patients. Depression could be a concern for people on long-term missions far from Earth who don’t expect to set foot on solid ground for years, and Roberts and Badran said TMS could be a useful and space-saving tool to pack on long-term space missions, rather than an entire pharmacy’s worth of medications.

“Ultimately, you don’t want to go to Mars or an interplanetary mission with all these medications. And you can’t easily set up a chemistry lab to synthesize all of them. So TMS would be a very clear, easy solution for neuropsychiatric issues. That’s the long 20-year vision,” Badran said.

It also has the potential to keep astronauts in good shape cognitively on long-term flights so they’re ready to get to work when they land on the moon or the red planet.

But first, researchers must figure out what a “normal” reading in zero gravity should look like.

It’s already known that medications metabolize differently when a person is in space. Astronauts who take sleeping pills, for example, have to figure out through trial and error the proper dosage in space, Roberts said.

“If there were a way to keep the brain in shape on the way to Mars, that would be very useful. That’s why NASA is interested in this technology. But in order to use it in space, we have to understand, ‘Is there a difference in the way astronauts respond to it here on Earth versus up in space?'”

Donna Roberts, M.D.

And Roberts’ previous research, comparing astronauts’ brain MRIs before and after a trip to the International Space Station, showed physical changes in the brain that correlated to changes in the astronauts’ motor skills and cognitive performance.

“If there were a way to keep the brain in shape on the way to Mars, that would be very useful. That’s why NASA is interested in this technology. But in order to use it in space, we have to understand, ‘Is there a difference in the way astronauts respond to it here on Earth versus up in space?’ just like the difference they experience in medications. So that was what this study was really based on,” she said.

And this is where the scientists got to have a little fun. To test TMS in zero gravity, they would board a special plane operated by Zero Gravity Corporation, which offers zero gravity flights for personal adventure, media productions and research.

The plane, dubbed G-Force One, flies a series of arcs, heading upward at 45 degrees and then back down at 45 degrees. For the brief 20 to 30 seconds between going up and coming down, everyone in the plane becomes weightless. Anything not bolted down floats up. And that mere 20- to 30-second window was the time during which Roberts and Badran had to run their TMS test.

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