Figure 2.

Change in cognitive performance in the head-down tilt bed rest (HDBR) period relative to pre-HDBR baseline. Estimates reflect z-scores based on the mean and standard deviation of pre-HDBR baseline performance. Error bars reflect unadjusted 95% confidence intervals. A: estimates for the control group (ambient CO₂, n = 8, 6 men) and the CO₂ group (3.73 mmHg CO₂, n = 11, 6 men); B: estimates for the difference between the CO₂ group and the control group; *adjusted P < 0.05; **adjusted P < 0.01; ***adjusted P < 0.001; ****adjusted P < 0.0001. ALL, scores averaged across cognitive domains; AM, abstract matching; BART, balloon analog risk test; DSST, digit symbol substitution test; ERT, emotion recognition test; F2B, fractal 2-back; HDBR, head-down tilt bed rest; LOT, line orientation test; MP, motor praxis; MRT, matrix reasoning test; PVT, psychomotor vigilance test; VOLT, visual object learning test.