Figure 1.

First-level analysis of longitudinal brain MRI CO₂ stress testing in one physiological post-concussion disorder patient during the symptomatic (A) and clinically recovered stages of injury (B). In each case the hot voxels (orangish hues) indicate where voxels have responded (at the p = 0.001 level; t-statistic = 3.11) to the triple CO₂ stimulus as delivered by the model-based prospective end-tidal targeting device as outlined in the methodology based on the general linear model constructed in the SPM analysis. A colored voxel indicates that the BOLD response increased when the CO₂ stimulus increased and decreased as the CO₂ stimulus decreased during the applied triple stimulus. The cold voxels (bluish hues) indicate where voxels have responded (at the p = 0.001 level; t-statistic = 3.11) in an inverse manner to the triple CO₂ stimulus – that is the BOLD signal decreased when the CO₂ signal increased and vice versa. Where the voxels remain gray the anatomic image template shows through indicating that the chosen level of statistical significance was not attained. In each study, an individualized inclusive mask was applied to eliminate artifactual voxels (see description in the methodology and a representative mask in Supplementary Material). The color bar numbers indicate the value of the t-statistic attained for the color displayed.