This is your brain in space — and it does not look pretty. Scientists studying the effects of radiation in rodents say that astronauts’ exposure to galactic cosmic rays could face a host of cognitive problems, including chronic dementia.
Published in the journal Scientific Reports, the study follows another report published last year that showed somewhat shorter-term brain effects of cosmic rays. The current study symbolizes a much bigger concern.
“This is not positive news for astronauts deployed on a two-to-three-year round trip to Mars,” study author Charles Limoli, a radiation expert at the University of California Irvine, said in a news release.
“Space poses unique hazards to astronauts. Exposure to these particles can lead to a range of potential central nervous system complications that can occur during and persist long after actual space travel — such as various performance decrements, memory deficits, anxiety, depression, and impaired decision-making.
“Many of these adverse consequences to cognition may continue and progress throughout life,” he added.
Zapping Rodents with Cosmic Rays
For the study, rodents were exposed to charged particles at a NASA facility and sent to UCI for study. Six months after exposure, the scientists still discovered noteworthy amounts of brain inflammation and neural imagery. Imaging tests showed the brain’s neural network was weakened through a decrease in dendrites and spines on these neurons, which interferes with signals within the brain. The rodents also exhibited poor performance on behavioral tasks built to test learning and memory.
Furthermore, the study team found the radiation affected “fear extinction,” an active system involving the brain’s suppression past unpleasant and stressful events. Its effects can be seen when someone who almost drowned learns appreciate swimming again.
“Deficits in fear extinction could make you prone to anxiety,” Limoli said, “which could become problematic over the course of a three-year trip to and from Mars.”
The new study is part of a NASA program looking into how space radiation affects astronauts and studying methods to reduce those effects, research that is fundamental to further human exploration of space as NASA plans for missions to Mars and beyond.
Partial solutions are being explored, Limoli said. Spacecraft might be built to include areas of higher shielding, like areas used for rest and sleep. However, these highly charged cosmic particles will enter the ship nonetheless, he added, “and there is really no escaping them.”