title: Altered baseline brain activity with 72 h of simulated microgravity--initial evidence from resting-state fMRI.
abstract: To provide the basis and reference to further insights into the neural activity of the human brain in a microgravity environment, we discuss the amplitude changes of low-frequency brain activity fluctuations using a simulated microgravity model. Twelve male participants between 24 and 31 years old received resting-state fMRI scans in both a normal condition and after 72 hours in a -6° head down tilt (HDT). A paired sample t-test was used to test the amplitude differences of low-frequency brain activity fluctuations between these two conditions. With 72 hours in a -6° HDT, the participants showed a decreased amplitude of low-frequency fluctuations in the left thalamus compared with the normal condition (a combined threshold of P<0.005 and a minimum cluster size of 351 mm(3) (13 voxels), which corresponded with the corrected threshold of P<0.05 determined by AlphaSim). Our findings indicate that a gravity change-induced redistribution of body fluid may disrupt the function of the left thalamus in the resting state, which may contribute to reduced motor control abilities and multiple executive functions in astronauts in a microgravity environment.
authors.affiliation: Department of Psychology, School of Aerospace Medicine, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liao
authors.forename: Jinsong
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Huang
authors.forename: Yibin
authors.initials: Y
authors.lastname: Xi
authors.forename: Qianru
authors.initials: Q
authors.lastname: Zhang
authors.forename: Tianli
authors.initials: T
authors.lastname: Zhu
authors.forename: Xufeng
authors.initials: X
authors.lastname: Liu
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012146:Rest / Q000502:physiology*; D013788:Thalamus / Q000502:physiology; D013997:Time Factors; D018474:Weightlessness Simulation; D055815:Young Adult