Space radiation, which will be exposed to the crews of interplanetary spacecraft for a long time, leads to a decrease in cognitive abilities and an increase in anxiety.
Cosmic radiation remains one of the main obstacles to truly long manned missions. Some cosmonauts spend quite long periods on the ISS, but here they are in near-earth orbit, under the protection of our planet's global magnetosphere. Doses that threaten during flights to other planets are much higher and more dangerous. One side of this risk has been demonstrated by researchers at the University of California, Irvine.
Charles Limoli and his colleagues conducted experiments with laboratory mice, exposing them to constant exposure to low doses of radiation for six months. As a result, the animals developed problems with memory and learning, and showed signs of chronic stress and high anxiety. They were apprehensive about dark corners and shadows, they were less able to remember new stimuli, and they struggled less when placed in an aquatic aquarium.
Scientists emphasize that the radiation exposure was low and approximately corresponded to what the astronauts will face in reality. They write about this in an article published in the eNeuro magazine. The composition of the radiation also mimicked cosmic radiation, including gamma photons and heavy neutrons. 40 mice were exposed to it, another 40 lived under normal conditions - as a control group. The condition and cognitive abilities of the animals were tested before and after the experiment.
Then, six months after the cessation of radiation exposure, the mice were euthanized to conduct studies of brain tissue and their ability to recover from relatively moderate damage. Unfortunately, hopes did not materialize - and the neurons of the rodents exposed to radiation showed noticeable differences.
However, scientists note that not all animals reacted to radiation in the same way: while some had significant cognitive impairment and changes in nerve tissues, they did not change so much in others. Perhaps, in the future, such a "predisposition" will become an important element in the selection of crews for long-range space missions.