title: Default network connectivity decodes brain states with simulated microgravity.
abstract: With great progress of space navigation technology, it becomes possible to travel beyond Earth's gravity. So far, it remains unclear whether the human brain can function normally within an environment of microgravity and confinement. Particularly, it is a challenge to figure out some neuroimaging-based markers for rapid screening diagnosis of disrupted brain function in microgravity environment. In this study, a 7-day -6° head down tilt bed rest experiment was used to simulate the microgravity, and twenty healthy male participants underwent resting-state functional magnetic resonance imaging scans at baseline and after the simulated microgravity experiment. We used a multivariate pattern analysis approach to distinguish the brain states with simulated microgravity from normal gravity based on the functional connectivity within the default network, resulting in an accuracy of no less than 85 % via cross-validation. Moreover, most discriminative functional connections were mainly located between the limbic system and cortical areas and were enhanced after simulated microgravity, implying a self-adaption or compensatory enhancement to fulfill the need of complex demand in spatial navigation and motor control functions in microgravity environment. Overall, the findings suggest that the brain states in microgravity are likely different from those in normal gravity and that brain connectome could act as a biomarker to indicate the brain state in microgravity.
authors.affiliation: College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073 Hunan People's Republic of China.
authors.forename: Ling-Li
authors.identifier: 0000-0002-0515-256X
authors.initials: LL
authors.lastname: Zeng
authors.affiliation: Department of Psychology, Fourth Military Medical University, Xi'an, 710032 Shaanxi People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liao
authors.affiliation: College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073 Hunan People's Republic of China.
authors.forename: Zongtan
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073 Hunan People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Shen
authors.affiliation: College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073 Hunan People's Republic of China.
authors.forename: Yadong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Psychology, Fourth Military Medical University, Xi'an, 710032 Shaanxi People's Republic of China.
authors.forename: Xufeng
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Mechatronics and Automation, National University of Defense Technology, Changsha, 410073 Hunan People's Republic of China.
authors.forename: Dewen
authors.initials: D
authors.lastname: Hu
keywords: Connectome; Default network; Functional magnetic resonance imaging; Microgravity; Multivariate pattern analysis