A new study revealed how radiation from deep space missions can affect the brain functions of astronauts. According to the researchers, being exposed to space radiation can cause various long-term effects such as memory loss, learning issues and social anxiety.

The study was carried out by a team of radiation biologists and published in the online journal eNeuro.

Previous studies have focused on the effects of space radiation on the cells of humans, with some findings pointing to the development of cancer. According to these studies, space radiation affects astronauts once they venture out of Earth’s orbit, which is no longer protected by the planet’s magnetic field.

In the new study, the biologists replicated the effects of radiation in space on humans by using mice as their primary subjects. After exposing the test animals to low-dose radiation for a total of six months, the researchers began seeing changes in the subjects’ cognitive functions.

Specifically, the researchers noted that long-term exposure to radiation impaired the signaling operations of the brain’s prefrontal cortex and hippocampus. Because of this, the subjects displayed problems related to their memory and learning capabilities.

The study’s co-author Charles Limoli of the University of California noted that their findings supported those from the team’s previous research.

“This study now shows that radiation delivered at space relevant dose rates over extended times elicits adverse neurocognitive effects similar to our past studies using dose rates that were about 400 times higher,” he told CNN.

Aside from learning and memory, the researchers also observed changes in the social behavior of the subjects that were exposed to radiation. Unlike the mice that weren’t subjected to radiation, the irradiated subjects avoided interactions. This led the researchers to conclude that the experiment also affected the brain’s amygdala, causing anxiety among the subjects.

With various space agencies such as NASA now planning on human missions to deep space, the study serves as a warning regarding the long term effects of cosmic radiation.

“Our work is just one study and the results must be replicated, but it does raise the sobering possibility that galactic cosmic radiation may represent a significant obstacle to deep space travel,” the researchers said in a statement.