In a study by researchers from the University of California, Irvine and elsewhere, exposure to chronic, low dose radiation — the conditions present in deep space — produced serious neurocognitive complications in mice.
Radiation is known to disrupt signaling among other processes in the brain.
However, previous experiments used short-term, higher dose-rate exposures of radiation, which does not accurately reflect the conditions in space.
“Our study represents the first to document the significant adverse consequences of space relevant radiation dose rates on the brain, and points to the heightened risks associated with NASA’s upcoming plans for travel to Mars,” said University of California, Irvine’s Professor Charles Limoli and colleagues.
To investigate how deep space travel could affect the nervous system, the researchers used a new neutron irradiation facility, capable of simulating the realistic low dose rates.
They exposed mice to chronic, low dose (18 centiGrays) radiation for six months.
They found that the radiation exposure impaired cellular signaling in the hippocampus and prefrontal cortex, resulting in learning and memory impairments.
The team also observed increased anxiety behaviors, indicating that the radiation also impacted the amygdala.
“During a deep space mission approximately one in five astronauts would experience anxiety-like behavior and one in three would experience certain levels of memory impairments,” Professor Limoli and co-authors said.
“Additionally, the astronauts may struggle with decision-making.”
The study was published online this week in the journal eNeuro.
M.M. Acharya et al. New concerns for neurocognitive function during deep space exposures to chronic, low dose rate, neutron radiation. eNeuro, published online August 5, 2019; doi: ENEURO.0094-19.2019