Back in 2019, a study on mice was released that set out to investigate how deep space travel would impact the nervous system and found radiation exposure hurt cellular signaling in the hippocampus and prefrontal cortex of the brain leading to learning and memory difficulties. The researchers also saw the mice exhibit behaviors associated with anxiety, implying the radiation can harm the amygdala.
Now, a new study published in Science Advances is revealing that male mice exposed to radiation similar to that encountered by humans on long space missions experienced problems with spatial learning. The researchers conducted several tests to evaluate the mice's spatial learning abilities after being exposed to galactic cosmic radiation.
In one of the tests, the researchers taught the mice to find a platform hidden under opaque water. To achieve this task, the mice had to rely on instructions given by the researchers prior to galactic cosmic radiation exposure.
The results indicated that the male mice made more mistakes than the control group (who had not been exposed to radiation). The female mice, however, did not. The researchers also found that a diet of food designed to deplete microglia (immune cells in the brain) prevented spatial learning impairment.
"This research in line with others suggests that we need to consider the effects of deep space radiation for the astronauts, we need to find mitigators that can help," Susanna Rosi, a researcher at the University of California, San Francisco, told Space.com in an email. "The research also tells us that mitigators currently approved in humans to deplete microglia could be used by astronauts!"
Finally, the researchers were able to identify a biomarker associated with the mice that were more likely to be negatively impacted by radiation exposure. This could one day be used to evaluate which astronauts are more likely to suffer the consequences of radiation exposure.