Figure 4.

(A, B) Ramp test results for subject 6 seated showing breath-by-breath measures of PetCO₂, MCAv, HR and MAP. Graph A on the left shows the time course of the variables and graph B on the right shows the absolute MCAv and MAP responses to PetCO₂. The lines in graph B show the analyses used to calculate CVR. The Sig analysis is indicated by the solid purple line, with the baseline PetCO₂-point marked as a circle and the tangent to the sigmoid curve at that point marked as a black line, and the Lin analysis is indicated by the dotted line. (C, D) Ramp test results from subject 4 seated. Graph A on the left shows the breath-by-breath measures of PetCO₂, MCAv, MCAc, MAP and HR during the ramp change in PetCO₂. Graph B on the right shows the relative MCAv, MCAc and the MAP responses to PetCO₂, with the latter showing the sub and superthreshold linear fits to the data. The MAP threshold is indicated by arrows on each graph. In graph B, the solid lines show the fitted sigmoidal curve of the Sig analysis and the dotted lines, the linear regression of the Lin analysis. The axes for each variable are as indicated and the units are noted with the color-coded variable labels.