Sensory network segregation as a predictor of post spaceflight balance impairments and sensory re-weighting

Exposure to microgravity results in transient sensorimotor performance declines when crewmembers return to Earth, likely due to sensory re-weighting. This poses performance risks following gravitational transitions, such as arriving on the Moon or Mars. Here, we examined whether sensory brain network segregation (how independently a given network functions) in astronauts prior to an International Space Station mission would predict balance post-flight. Intraclass correlation analysis showed high test-retest reliability for all sensory network segregation measures. Indices of the Parietal Operculum 2 network (OP2) segregation pre-flight significantly predicted balance performance. Specifically, greater segregation predicted poorer balance on day one following return to Earth (Left OP2), better balance four days post-flight (Left and Right OP2) and greater balance improvements from one to four days post-flight. Results suggest that OP2 segregation may index plasticity of sensory weighting processes; that is, the degree of vestibular input down-weighting measured initially post-flight and extent of recovery over subsequent four days.