Exposure to low (10 cGy) doses of 4He ions leads to an apparent increase in risk taking propensity in female rats

The planned missions to the Moon and Mars will present more significant health challenges to astronauts compared to low earth orbit missions. During deep space missions, astronauts will be constantly exposed to Space radiation (SR). Multiple rodent studies suggest that < 25 cGy of SR impairs performance in executive functions, which play a key role in advanced cognitive processes, but also regulate response inhibition and impulse control. There is the possibility that SR exposure may exacerbate aberrant behaviors evoked by psychological stress related to exposure to isolated and confined (ICE) hostile environment or independently induce additional aberrant behaviors. This study has determined that female Wistar rats exposed to 10 cGy of 250 MeV/n He had an increased risk taking propensity (RTP)\compared to shams. The increased RTP of the He-exposed rats was associated with significantly increased reaction times during the trials, suggesting a SR-induced loss of processing speed. The response times of the He-exposed rats were even further reduced in trials that immediately followed a loss, raising the possibility that conflict and interference avoidance may be impaired after SR exposure. Whether these findings occur following other types of SR exposure, and/or in male rats remains to be determined. •First study to demonstrate that space radiation exposure impacts risk taking predisposition.•First definitive data that space radiation exposure impacts processing speed.•Expansion of the scope of CNS processes that space radiation exposure impacts.