How Does Cosmic Radiation Affect the Brain? One USU Professor Aims to Find Out

By Ian Neligh

Since astronaut Alan Shepard’s sub-orbital flight 61 years ago, historic developments in NASA’s exploration of space have included everything from the Apollo program to the James Webb Space Telescope.

NASA is now planning on a human mission to Mars by late 2030 or early 2040 — but before any long-term space flight missions can occur, research must be conducted into how humans will respond to prolonged exposure to cosmic radiation.

That’s where Dr. Catherine Davis-Takacs comes in.

Davis-Takacs is a Uniformed Services University of the Health Sciences (USU) Pharmacology and Molecular Therapeutics assistant professor and the principal investigator on a research project looking into the effects of cosmic radiation on the human brain.

Davis-Takacs’s project for NASA, “Neurobehavioral and CNS-Related Physiological Changes Following Space Radiation,” specifically looks at how exposure to ionizing radiation damages the central nervous system and what countermeasures are needed to protect cognitive function.

Prior research in this field has shown changes in the dopamine neurotransmitter systems and increased inflammatory responses in brains, impairing cognition — a serious issue when operating a spacecraft 300 million miles to Mars and then back again. Before NASA can send anyone to the red planet, a solution will need to be discovered, and that starts with her research.

Dr. Catherine Davis-Takacs says reducing the impact of radiation on astronauts could potentially include everything from shielding on the ships, drugs, and/or
even screening out people who are more sensitive for genetic reasons. (Photo courtesy of NASA)

“In terms of space radiation there’s a lot that we don’t know,” says Davis-Takacs. “It’s a different form of radiation than what most cancer patients receive.”

Davis-Takacs started her lab, which is located within USU’s Armed Forces Radiobiology Research Institute, in 2020, bringing with her the ongoing research project she began during postdoctoral training at Johns Hopkins University School of Medicine several years ago.

According to NASA, determining the consequences of living in a “space radiation environment” is one of the organization’s highest research priorities.

“(The research is being done) to understand the risk… can it be managed by some type of countermeasure or multiple countermeasures? Can selection criteria be applied to help mitigate this risk? Are there people who are more or less sensitive? How sensitive is the brain to these types of radiation exposures? Are there any pharmaceuticals that can be used to mitigate these types of effects?” Davis-Takacs says.

She adds the radiation from space is different from the types of radiation that civilians or military personnel would be exposed to in either an occupation or a medical setting. She says that even the radiation astronauts are exposed to on the International Space Station (ISS) is lower than what astronauts would experience during longer durations of space flight.

“The ISS is protected by the magnetosphere of the Earth and while it can be an experimental test bed for lots of things — it can’t be that for radiation from a trip to Mars because the amount of radiation astronauts are exposed to on the ISS isn’t equivalent to what we’re doing…,” Davis-Takacs says.

For example, she points to the astronauts who visited the moon and how radiographic film was used to show the track structures of the ions moving through the film.

“You can see in the short time they were in space outside of the magnetosphere just sort of what they were bombarded with,” Davis-Takacs says. “They didn’t have any protection, especially when they were walking on the moon. They reported they saw ‘light flashes’ and most scientists today now think those light flashes that they thought they saw were ions hitting their retinas.”

To replicate that type of radiation, Davis-Takacs says she uses the accelerator at Brookhaven National Laboratory and its NASA Space Radiation Laboratory, which can simulate what astronauts might be exposed to in terms of the dose rates and types of ions.

“We’ve been studying the neurobehavioral effects…,” Davis-Takacs says. “We study chronic exposures where we deliver a little tiny dose every single day — which is more like what an astronaut would experience if they were in space for three years and would be bombarded constantly with radiation but at really low doses and dose rates.”

She says even low levels of radiation can change the way neurons function in the brain.

“It is not about killing cells necessarily in the brain — it is more about how they function and inducing chronic neural inflammation,” Davis-Takacs says. “If some people are able to resolve that inflammation, then there’s a chance that they might be able to recover. If they get lower total doses, they will fare better in the future.”

The history of space flight in the U.S. has been about discovering problems and finding clever solutions such as improving bone density for astronauts staying in microgravity.

“If you look at NASA’s list of major risks (how radiation affects the brain) is one of their major unsolved ones,” Davis-Takacs says. “But there are lots of other body systems that they’ve been able to come up with really great solutions for.”

She says ways of reducing the impact of radiation on astronauts in the future could potentially include everything from shielding on the ships, drugs, and or even screening out people who are more sensitive for genetic reasons.

As long as humankind dreams of exploring the solar system and what lies beyond, scientists like David-Takacs are ready to identify problems, find solutions and, ultimately, make it possible to aim for the stars.