Department of Applied Physiology and Kinesiology, University of Florida, 1864 Stadium Rd., Gainesville, FL 32611, United States.
Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany.
Neuroimage. 2021 Jan 15;225:117450. doi: 10.1016/j.neuroimage.2020.117450. Epub 2020 Oct 16.
Astronauts are exposed to microgravity and elevated CO levels onboard the International Space Station. Little is known about how microgravity and elevated CO combine to affect the brain and sensorimotor performance during and after spaceflight. Here we examined changes in resting-state functional connectivity (FC) and sensorimotor behavior associated with a spaceflight analog environment. Participants underwent 30 days of strict 6 head-down tilt bed rest with elevated ambient CO (HDBR+CO). Resting-state functional magnetic resonance imaging and sensorimotor assessments were collected 13 and 7 days prior to bed rest, on days 7 and 29 of bed rest, and 0, 5, 12, and 13 days following bed rest. We assessed the time course of FC changes from before, during, to after HDBR+CO. We then compared the observed connectivity changes with those of a HDBR control group that underwent HDBR in standard ambient air. Moreover, we assessed associations between post-HDBR+CO FC changes and alterations in sensorimotor performance. HDBR+CO was associated with significant changes in functional connectivity between vestibular, visual, somatosensory and motor brain areas. Several of these sensory and motor regions showed post-HDBR+CO FC changes that were significantly associated with alterations in sensorimotor performance. We propose that these FC changes reflect multisensory reweighting associated with adaptation to the HDBR+CO microgravity analog environment. This knowledge will further improve HDBR as a model of microgravity exposure and contribute to our knowledge of brain and performance changes during and after spaceflight.
宇航员在国际空间站上会暴露在微重力和高浓度二氧化碳环境中。目前还不太清楚微重力和高浓度二氧化碳如何结合起来，在航天飞行期间和之后影响大脑和感觉运动表现。在这里，我们研究了与航天飞行模拟环境相关的静息状态功能连接（FC）和感觉运动行为的变化。参与者接受了 30 天严格的 6 头低位卧床休息，同时提高了环境中的 CO（HDBR+CO）。在卧床休息前 13 天和 7 天、卧床休息第 7 天和第 29 天以及卧床休息后 0、5、12 和 13 天采集了静息态功能磁共振成像和感觉运动评估数据。我们评估了 HDBR+CO 期间、期间和之后 FC 变化的时间过程。然后，我们将观察到的连通性变化与在标准环境空气中进行 HDBR 的 HDBR 对照组进行了比较。此外，我们评估了 HDBR+CO 后 FC 变化与感觉运动表现改变之间的关联。HDBR+CO 与前庭、视觉、躯体感觉和运动大脑区域之间的功能连接发生显著变化。这些感觉和运动区域中的几个区域在后 HDBR+CO FC 变化与感觉运动表现的改变显著相关。我们提出，这些 FC 变化反映了与适应 HDBR+CO 微重力模拟环境相关的多感觉重新加权。这一知识将进一步改进 HDBR 作为微重力暴露模型，并有助于我们了解航天飞行期间和之后大脑和表现的变化。
