Simulated Space Radiation Exposure Effects on Switch Task Performance in Rats.

Area of Science:

• Space Medicine
• Neuroscience
• Radiation Biology

Background:

• Astronauts face significant galactic cosmic radiation (GCR) exposure during deep space missions, such as to Mars.
• Previous research indicates simulated GCR (GCRsim) can impair cognitive functions, but its effect on task switching remains unknown.
• Task switching is crucial for aviators and astronauts, requiring rapid adaptation to changing conditions.

Purpose of the Study:

• To investigate the impact of simulated GCR (GCRsim) exposure on task switching performance in a rodent model.
• To determine if GCRsim affects cognitive skills relevant to operational performance in spaceflight.

Main Methods:

• Male Wistar rats were exposed to either 10 cGy of ⁴He ions or GCRsim, alongside sham-exposed littermates.
• Animals were trained on a touchscreen task mimicking pilot warning light response tests.
• Performance was assessed in switch and repeat trials to measure response times and switch costs.

Main Results:

• GCRsim-exposed rats exhibited significantly slower response times in switch trials compared to sham controls.
• These rats showed significantly higher switch response ratios and absolute switch costs.
• Irradiated rats were more likely to fail high cognitive load training tasks.

Conclusions:

• Simulated GCR exposure significantly impairs task switching performance, with an absolute switch cost of approximately 700 ms.
• Such deficits could have serious operational implications for astronauts, potentially affecting mission safety and success.
• Further research is needed to understand the human relevance of these findings for Mars missions.