Senior author Dr. M. Kerry O'Banion, a professor in the University of Rochester Medical Center Department of Neurobiology and Anatomy, first author Jonathan Cherry, a graduate student, and colleagues, said space is full of radiation, but Earth's magnetic field generally protects the planet and its people.
However, once astronauts leave orbit, they are exposed to a constant shower of various radioactive particles, and the longer an astronaut is in deep space, the greater the exposure.
A portion of the research was conducted at the NASA Space Radiation Laboratory at Brookhaven National Laboratory on Long Island, N.Y., to take advantage of its particle accelerators, which, by colliding matter together at very high speeds, could reproduce the radioactive particles found in space.
At Brookhaven, the animals were exposed to various doses of radiation, including levels comparable to what astronauts would experience during a mission to Mars. Cherry evaluated the cognitive and biological impact of the exposure.
The study, published in the journal PLOS ONE, found mice exposed to radiation were far more likely to fail these tasks -- suggesting neurological impairment -- earlier than these symptoms would typically appear and the brains also showed signs of vascular alterations and a greater than normal accumulation of beta amyloid, linked to Alzheimer's disease.
"These findings clearly suggest that exposure to radiation in space has the potential to accelerate the development of Alzheimer's disease," O'Banion said in a statement.