Fig. 4.

Optical properties affect calculation of ${\mathrm{CMRO}}_2.$ Comparison of SFI (light blue), ${\mathrm{CMRO}}_2$ calculated using SFI (uncorrected ${\mathrm{CMRO}}_2$, dark blue), and ${\mathrm{CMRO}}_2$ calculated using $v_c$ (corrected ${\mathrm{CMRO}}_2$, red), which accounts for the effects of tissue optical properties on SFI. For ease of comparison, the three curves are normalized to their value at a point near the end of the washout period ($t\sim 4\min$). This correction reveals differences in the observed rates of change in ${\mathrm{CMRO}}_2$ during reperfusion and resumption of ECoG bursting, suggesting the need to take optical properties into account even for relative ${\mathrm{CMRO}}_2$ measurements.