Astronauts on deep space missions will be required to work autonomously and thus their ability to perform executive functions could be critical to mission success. Ground-based rodent experiments have shown that low (<25 cGy) doses of several space radiation (SR) ions impair various aspects of executive function. Translating ground-based rodent studies into tangible risk estimates for astronauts remains an enormous challenge, but should similar neurocognitive impairments occur in astronauts exposed to low-SR doses, a Numbers-Needed-to-Harm analysis (of the rodent data) predicts that approximately 30% of the astronauts could develop severe cognitive flexibility decrements. In addition to the health risks associated with SR exposure, astronauts have to contend with other stressors, of which inadequate sleep quantity and quality are considered to be major concerns. We have shown that a single session of fragmented sleep uncovered latent attentional set-shifting (ATSET) performance deficits in rats exposed to protracted neutron radiation that had no obvious defects in performance under rested wakefulness conditions. It is unclear if the exacerbating effect of sleep fragmentation (SF) only occurs in rats receiving protracted low-dose-rate-neutron radiation. In this study, we assessed whether SF also unmasks latent ATSET deficits in rats exposed to 5 cGy 600 MeV/n ²⁸Si ions. Only sham and Si-irradiated rats that had good ATSET performance (passing every stage of the test on their first attempt) were selected for study. Sleep fragmentation selectively impaired performance in the more complex IDR, EDS and EDR stages of the ATSET test in the Si-irradiated rats. Set-shifting performance has rarely been affected by SR exposure in our studies conducted with rats tested under rested wakefulness conditions. The consistent SF-related unmasking of latent set-shifting deficits in both Si- and neutron-irradiated rats suggests that there is a unique interaction between sleep fragmentation and space radiation on the functionality of the brain regions that regulate performance in the IDR, EDS and EDR stages of ATSET. The uncovering of these latent SR-induced ATSET performance deficits in both Si- and neutron-irradiated rats suggests that the true impact of SR-induced cognitive impairment may not be fully evident in normally rested rats, and thus cognitive testing needs to be conducted under both rested wakefulness and sleep fragmentation conditions.

要求执行深空任务的宇航员自主工作，因此他们执行行政职能的能力对于任务的成功至关重要。地面啮齿动物实验表明，低剂量（<25 cGy）的几种空间辐射（SR）离子会损害执行功能的各个方面。将地面啮齿类动物研究转化为对航天员的有形风险估计仍然是一项巨大的挑战，但是如果暴露于低SR剂量的宇航员发生类似的神经认知障碍，一项需要对啮齿类动物进行数据分析的研究表明： 30％的宇航员可能会出现严重的认知灵活性下降。除了与SR暴露相关的健康风险外，宇航员还必须与其他压力源抗衡，其中不足的睡眠量和质量被认为是主要问题。我们已经表明，一次零散的睡眠会暴露在长时间的中子辐射中的潜在注意注意力转移（ATSET）性能缺陷，而长期休息的中子辐射在静息清醒条件下没有明显的功能缺陷。目前尚不清楚睡眠碎片（SF）的加剧作用是否仅发生在接受长期低剂量率中子辐射的大鼠中。在这项研究中，我们评估了SF是否还能掩盖暴露于5 cGy 600 MeV / n的大鼠中潜在的ATSET缺陷。我们已经表明，一次零散的睡眠会暴露在长时间的中子辐射中的潜在注意注意力转移（ATSET）性能缺陷，而长期休息的中子辐射在静息清醒条件下没有明显的功能缺陷。目前尚不清楚睡眠碎片（SF）的加剧作用是否仅发生在接受长期低剂量率中子辐射的大鼠中。在这项研究中，我们评估了SF是否还能掩盖暴露于5 cGy 600 MeV / n的大鼠中潜在的ATSET缺陷。我们已经表明，一次零散的睡眠会暴露在长时间的中子辐射中的潜在注意注意力转移（ATSET）性能缺陷，而长期休息的中子辐射在静息清醒条件下没有明显的功能缺陷。目前尚不清楚睡眠碎片（SF）的加剧作用是否仅发生在接受长期低剂量率中子辐射的大鼠中。在这项研究中，我们评估了SF是否还能掩盖暴露于5 cGy 600 MeV / n的大鼠中潜在的ATSET缺陷。²⁸硅离子。仅选择具有良好ATSET性能（首次尝试通过测试的每个阶段）的假手术和Si照射的大鼠进行研究。睡眠碎片选择性地损害了用Si照射的大鼠的ATSET测试的更复杂的IDR，EDS和EDR阶段的性能。在我们的静息觉醒条件下对大鼠进行的研究中，SR暴露很少影响定档转换性能。在被Si和中子辐照的大鼠中，SF相关的潜在潜伏性位移缺陷的一致掩盖表明，睡眠碎片和空间辐射在调节IDR，EDS和EDS表现的大脑区域功能之间存在独特的相互作用。 ATSET的EDR阶段。