title: Disrupted resting-state functional architecture of the brain after 45-day simulated microgravity.
abstract: Long-term spaceflight induces both physiological and psychological changes in astronauts. To understand the neural mechanisms underlying these physiological and psychological changes, it is critical to investigate the effects of microgravity on the functional architecture of the brain. In this study, we used resting-state functional MRI (rs-fMRI) to study whether the functional architecture of the brain is altered after 45 days of -6° head-down tilt (HDT) bed rest, which is a reliable model for the simulation of microgravity. Sixteen healthy male volunteers underwent rs-fMRI scans before and after 45 days of -6° HDT bed rest. Specifically, we used a commonly employed graph-based measure of network organization, i.e., degree centrality (DC), to perform a full-brain exploration of the regions that were influenced by simulated microgravity. We subsequently examined the functional connectivities of these regions using a seed-based resting-state functional connectivity (RSFC) analysis. We found decreased DC in two regions, the left anterior insula (aINS) and the anterior part of the middle cingulate cortex (MCC; also called the dorsal anterior cingulate cortex in many studies), in the male volunteers after 45 days of -6° HDT bed rest. Furthermore, seed-based RSFC analyses revealed that a functional network anchored in the aINS and MCC was particularly influenced by simulated microgravity. These results provide evidence that simulated microgravity alters the resting-state functional architecture of the brains of males and suggest that the processing of salience information, which is primarily subserved by the aINS-MCC functional network, is particularly influenced by spaceflight. The current findings provide a new perspective for understanding the relationships between microgravity, cognitive function, autonomic neural function, and central neural activity.
authors.affiliation: Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China ; University of Chinese Academy of Sciences Beijing, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China.
authors.forename: Li-Lin
authors.initials: LL
authors.lastname: Rao
authors.affiliation: Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China.
authors.forename: Zhu-Yuan
authors.initials: ZY
authors.lastname: Liang
authors.affiliation: National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center Beijing, China.
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Chen
authors.affiliation: Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China ; University of Chinese Academy of Sciences Beijing, China.
authors.forename: Dang
authors.initials: D
authors.lastname: Zheng
authors.affiliation: National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center Beijing, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Tan
authors.affiliation: National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center Beijing, China.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Tian
authors.affiliation: National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center Beijing, China.
authors.forename: Chun-Hui
authors.initials: CH
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center Beijing, China.
authors.forename: Yan-Qiang
authors.initials: YQ
authors.lastname: Bai
authors.affiliation: National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center Beijing, China.
authors.forename: Shan-Guang
authors.initials: SG
authors.lastname: Chen
authors.affiliation: Key Laboratory of Behavioral Science and Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Li
keywords: anterior insula; cingulate cortex; functional connectivity; functional magnetic resonance imaging (fMRI); head-down tilt bed rest; resting state