Deep space flight missions beyond the Van Allen belt have the potential to expose astronauts to space radiation which may damage the central nervous system and impair function. The proposed mission to Mars will be the longest mission-to-date and identifying mission critical tasks that are sensitive to space radiation is important for developing and evaluating the efficacy of counter measures. Fine motor control has been assessed in humans, rats, and many other species using string-pulling behavior. For example, focal cortical damage has been previously shown to disrupt the topographic (i.e., path circuity) and kinematic (i.e., moment-to-moment speed) organization of rat string-pulling behavior count to compromise task accuracy. In the current study, rats were exposed to a ground-based model of simulated space radiation (5 cGy ²⁸Silicon), and string-pulling behavior was used to assess fine motor control. Irradiated rats initially took longer to pull an unweighted string into a cage, exhibited impaired accuracy in grasping the string, and displayed postural deficits. Once rats were switched to a weighted string, some deficits lessened but postural instability remained. These results demonstrate that a single exposure to a low dose of space radiation disrupts skilled hand movements and posture, suggestive of neural impairment. This work establishes a foundation for future studies to investigate the neural structures and circuits involved in fine motor control and to examine the effectiveness of counter measures to attenuate the effects of space radiation on fine motor control.

范艾伦带以外的深空飞行任务有可能使宇航员暴露在太空辐射中，这可能会损害中枢神经系统并损害功能。拟议的火星任务将是迄今为止最长的任务，确定对空间辐射敏感的关键任务对于制定和评估反措施的有效性很重要。已经在人类、大鼠和许多其他物种中使用拉弦行为评估了精细运动控制。例如，先前已经证明局灶性皮质损伤会破坏地形（即路径迂回）和运动学（即，瞬间速度）组织大鼠拉线行为计数以损害任务准确性。在目前的研究中，大鼠暴露于模拟空间辐射的地面模型 (5 cGy ²⁸硅），并使用拉弦行为来评估精细运动控制。辐照大鼠最初需要更长的时间将未配重的绳子拉入笼子中，表现出抓住绳子的准确性受损，并表现出姿势缺陷。一旦老鼠换上负重绳，一些缺陷就会减轻，但姿势不稳定仍然存在。这些结果表明，单次暴露于低剂量的空间辐射会破坏熟练的手部动作和姿势，暗示神经损伤。这项工作为未来的研究奠定了基础，以调查精细运动控制中涉及的神经结构和电路，并检查减轻空间辐射对精细运动控制影响的对策的有效性。