FIGURE 1.

Testing timelines. Top: testing timeline for the HDBR + CO₂ group, who completed 30 days of head down tilt bed rest (HDBR) with 0.5% atmospheric CO₂. Bottom: testing timeline for the HDBR group, who completed 70 days of HDBR with normal atmospheric CO₂ levels. BDC = baseline data collection; HDBR = head down tilt bed rest; R = recovery. Functional MRI and behavioral data were collected at all time points specified here. Stars indicate the three time points used to create the slope images for between-group comparisons.