Muscle synergies of multidirectional postural control in astronauts on Earth after a long-term stay in space
| Autor: | Shota Hagio, Akihiko Ishihara, Masahiro Terada, Hiroko Tanabe, Benio Kibushi, Akira Higashibata, Shin Yamada, Satoshi Furukawa, Chiaki Mukai, Noriaki Ishioka, Motoki Kouzaki |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Journal of Neurophysiology. 127:1230-1239 |
| ISSN: | 1522-1598 0022-3077 |
| DOI: | 10.1152/jn.00232.2021 |
| Popis: | Movements of the human biological system have adapted to the physical environment under the 1-g gravitational force on Earth. However, the effects of microgravity in space on the underlying functional neuromuscular control behaviors remain poorly understood. Here, we aimed to elucidate the effects of prolonged exposure to a microgravity environment on the functional coordination of multiple muscle activities. The activities of 16 lower limb muscles of 5 astronauts who stayed in space for at least 3 mo were recorded while they maintained multidirectional postural control during bipedal standing. The coordinated activation patterns of groups of muscles, i.e., muscle synergies, were estimated from the muscle activation datasets using a factorization algorithm. The experiments were repeated a total of five times for each astronaut, once before and four times after spaceflight. The compositions of muscle synergies were altered, with a constant number of synergies, after long-term exposure to microgravity, and the extent of the changes was correlated with the increased velocity of postural sway. Furthermore, the muscle synergies extracted 3 mo after the return were similar in their activation profile but not in their muscle composition compared with those extracted in the preflight condition. These results suggest that the modularity in the neuromuscular system became reorganized to adapt to the microgravity environment and then possibly reoptimized to the new sensorimotor environment after the astronauts were reexposed to a gravitational force. It is expected that muscle synergies can be used as physiological markers of the status of astronauts with gravity-dependent change. |
| Databáze: | OpenAIRE |
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