Astronauts on the planned mission to Mars will be exposed to galactic cosmic radiation (GCR), with proton and He particles accounting (in approximately equal amounts) for ∼75% of the equivalent dose. Exposure to ≤15 cGy of space radiation ions with Z ≥ 15 particles has been shown to impair various executive functions, including attentional set shifting and creative problem-solving in rats. Executive functions also regulate social interactions and mood. Should space radiation exposure alter these executive functions as it does cognitive flexibility, there is the possibility of altered interactions among crew members and team cooperativity during prolonged space exploration. This study characterized the effects of ≤10 cGy 400 MeV/n of ⁴He particles on cognitive flexibility and social interaction (within freely interacting dyads) in male Wistar rats. Exposure to ≥1 cGy ⁴He ions induced deficits in the SD and/or CD stages of the attentional set shifting (ATSET) task, as reported after exposure to Z ≥ 15 space radiation ions. Should similar effects occur in astronauts, these data suggest that they would have a reduced ability to identify key events in a new situation and would be more easily distracted by extraneous variables. The irradiated rats were also screened for performance in a task for unconstrained cognitive flexibility (UCFlex), often referred to as creative problem-solving. There was a marked dose-dependent change in UCFlex performance with ∼30% of rats exposed to 10 cGy being unable to solve the problem, while the remaining rats took longer than the sham-irradiated animals to resolve the problem. Importantly, performance in the ATSET test was not indicative of UCFlex performance. From a risk assessment perspective, these findings suggest that a value based on a single behavioral end point may not fully represent the cognitive deficits induced by space radiation, even within the cognitive flexibility domain. Rats that received 5 cGy ⁴He ion irradiation had a significantly lower level of interaction toward their sham-irradiated partners in a non-anxiogenic (uncaged) dyad interactions study. This is consistent with the social withdrawal previously observed in space radiation-exposed male mice in a three-chamber test. ⁴He-irradiated rats exhibited a significantly higher incidence and duration of self-grooming, which is even more concerning, given that their dyad partners were able to physically interact with the irradiated rats (i.e., touching/climbing over them). This study has established that exposure of male rats to “light” ions such as He affects multiple executive functions resulting in deficits in both sociability and cognitive flexibility, and possibly affective behavior (reward valuation). Further studies are needed to determine if these space radiation-induced co-morbidities are concomitantly induced within individual rats.

执行计划中的火星任务的宇航员将暴露于银河宇宙辐射 (GCR)，其中质子和 He 粒子（数量大致相等）约占等效剂量的 75%。暴露于 ≤15 cGy 且 Z ≥ 15 粒子的空间辐射离子已被证明会损害大鼠的各种执行功能，包括注意力转移和创造性解决问题的能力。执行功能还调节社交互动和情绪。如果太空辐射暴露会像影响认知灵活性一样改变这些执行功能，那么在长时间的太空探索过程中，机组成员之间的互动和团队合作可能会发生改变。本研究描述了 ≤10 cGy 400 MeV/n ⁴ He 粒子对雄性 Wistar 大鼠认知灵活性和社交互动（在自由互动的二元组内）的影响。根据暴露于 Z ≥ 15 空间辐射离子后的报告，暴露于 ≥1 cGy ⁴ He 离子会导致注意力转移 (ATSET) 任务的 SD 和/或 CD 阶段出现缺陷。如果类似的效应发生在宇航员身上，这些数据表明，他们在新情况下识别关键事件的能力会下降，并且更容易受到无关变量的干扰。还对受辐射的老鼠进行了无约束认知灵活性（UCFlex）任务的表现筛查，通常被称为创造性解决问题。 UCFlex 性能存在明显的剂量依赖性变化，约 30% 暴露于 10 cGy 的大鼠无法解决问题，而其余大鼠比假辐射动物需要更长的时间才能解决问题。重要的是，ATSET 测试中的性能并不代表 UCFlex 的性能。 从风险评估的角度来看，这些发现表明，基于单一行为终点的值可能无法完全代表空间辐射引起的认知缺陷，即使在认知灵活性领域也是如此。在一项非焦虑（非笼养）二元相互作用研究中，接受 5 cGy ⁴ He 离子照射的大鼠与其假照射伙伴的相互作用水平显着降低。这与之前在三腔测试中在暴露于太空辐射的雄性小鼠中观察到的社交退缩是一致的。 ⁴经 He 照射的大鼠表现出明显更高的自我梳理发生率和持续时间，这甚至更令人担忧，因为它们的二元伙伴能够与受照射的大鼠进行身体互动（即触摸/爬过它们）。这项研究已经证实，雄性大鼠暴露于“轻”离子（例如 He）会影响多种执行功能，导致社交能力和认知灵活性缺陷，并可能导致情感行为（奖励评估）缺陷。需要进一步的研究来确定这些空间辐射引起的并发症是否在个体大鼠中同时引起。