Proton-induced Behavioral Alterations approved Cognitive Dysfunction

Abstract

Abstract A long-term space exploration faces extremely hazardous environmental stresses, and the exposure to space radiation has been considered as one of the most dangerous factors in Space. For the safety of astronauts, even a low amount of proton exposure in space radiation is necessary to be understood to protect their body systems and maintain the functional balance. However, the endpoint test based on behavioral responses lead to an undetermined consequence in the functional declines by producing the inconsistent results despite of the accumulated proofs in the molecular and the cellular damages by proton. To clarify the systemic link between the proton exposure and the cognitive decline in behaviors, some fundamental behavioral tests, such as rota-rod, open field test, and novel object recognition, were revisited, and the proton-induced alteration was examined by computing behavioral markers in time basis. A portion out of total population (28 SD rats) involved for each test, and the relevant behavioral markers in time were calculated to assess the proton-induced effects in emotion, locomotion and memory. The examination in 3 months of behavioral responses after the different amount of exposure (control, 30cGy-, and 1Gy-exposed animals) identified the emotional and locomotive alterations while few memory-related changes were observed. The computed behavioral markers suggested a quantitative approach to demonstrate the cognitive behavioral effects by a low amount of proton (30cGy) as well as the direct relation between the proton exposure and the cognitive alteration.