Transient gray matter decline during antarctic isolation: Roles of sleep, exercise, and cognition

Fig. 1. Crewmembers show a transient decrease in gray matter volume in some cortical brain regions after a winter-over at the Concordia station. Gray matter brain volume was lower in the temporal and parietal lobes immediately after winter-over (Post1; A) as compared to baseline but returned to baseline levels five months after return from Antarctica (Post2; B). Trajectory of change for each cortical gray matter volume is shown in C. Error bars reflect 95% confidence intervals. All gray matter volumes are normalized to flying phantoms who were scanned at each site. Sensitivity analyses, individual trajectories and analyses for control subjects who did not winter-over are shown in the Supplement Note 1. Significance values are represented as **p < 0.01; ***p < 0.001. All p-values shown are Bonferroni corrected. Images were created using ggseg82.

Fig. 2. Crewmembers show a decrease in gray matter volume in several subcortical brain regions and increase in ventricular volume after a winter-over at the Concordia station. Gray matter brain volume was lower in Hippocampus, Pallidum and Thalamus immediately after winter-over (Post1, A and C) as compared to baseline. Hippocampus and Pallidum volumes returned to baseline levels five months after return from Antarctica (B, D), but Thalamus volume remained lower. Volume of the Lateral, 3rd and 4th Ventricles all increased after winter-over (A), (C). Volume of the Lateral and 3rd ventricles remained elevated five months after return from Antarctica (B, D). All volumes are normalized to flying phantoms who were scanned at each site. Sensitivity analyses, individual trajectories and analyses for control subjects who did not winter-over are shown in the Supplemental Note 1. Note: Total cerebral white matter volume also decreased from Pre to Post1, but is not highlighted in red. Significance values are represented as *p < 0.05, **p < 0.01; ***p < 0.001. All p-values shown are Bonferroni corrected. Error bars in C and D reflect 95% confidence intervals. Images were created using ggseg82.

Fig. 3. Effect size (Pearson’s r) between change (Post1 – Pre) in regional brain volume and average sleep, exercise, self-reported arousal measures, and cognitive performance during the winter-over. Cells in the table are labeled by positive (green) and negative (red) associations between change in brain volume and average behavior/performance. Positive correlation coefficients indicate that high values in the behavior/performance domain were associated with gray matter volume preservation, whereas negative correlation coefficients indicate high values in the behavior/performance domain were associated with gray matter volume loss. Cognition Tasks: PVT Psychomotor Vigilance Test, BART Balloon Analog Risk Test, DSST Digit Symbol Substitution Test, MRT Matrix Reasoning Test, ERT Emotion Recognition Test, LOT Line Orientation Test, AM Abstract Matching Test, NBCK N-back Working Memory Test, VOLT Visual Object Learning Test, MP Motor Praxis Test.