How Long-Term Space Travel Impacts the Brain: Cosmic Rays May Cause Dementia Symptoms

As space agencies look into long-term space travel, it's crucial to determine what kind of impact this travel will have on the human body. Now, scientists have discovered that cosmic rays may actually cause cognitive decline similar to dementia.

In order to better understand what effect that highly energetic charged particles might have on a body, the researchers exposed rodents to charged particle irradiation. These particles are much like those found in the galactic cosmic rays that bombard astronauts during extended spaceflights.

The researchers found that exposure to these particles resulted in brain inflammation. This disrupted the transmission of signals among neurons. In addition, imaging revealed that the brain's communication network was impaired through reductions in the structure of nerve cells called dendrites and spines. Additional synaptic alterations in combination with the structural changes interfered with the capability of nerve cells to efficiently transmit electrochemical signals.

"This is not positive news for astronauts deployed on a two- to three-year round trip to Mars," said Charles Limoli, one of the researchers, in a news release. "Performance decrements, memory deficits, and loss of awareness and focus during spaceflight may affect mission-critical activities and exposure to these particles may have long-term adverse consequences to cognition throughout life."

Similar types of more severe cognitive dysfunction are actually common in brain cancer patients who have received various photon-based radiation treatments at much higher doses.

With that said, the new research does pave the way to solutions. Spacecraft could be designed to include areas of increased shielding, such as those used for rest and sleep. However, these highly energetic particles will still traverse the ship, and there's really no way to escape them.

Preventative treatments, however, may offer a partial solution. Currently, the scientists are working on pharmacological solutions involving compounds that scavenge free radicals and protect neurotransmission.

The findings are published in the journal Science Advances.

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