Figure 4.

The average fractional responses of cerebral blood flow (CBF), cerebral metabolic consumption of oxygen (CMRO₂), cerebral oxy-hemoglobin (HbO), cerebral deoxy-hemoglobin (HbR), and cerebral total hemoglobin (HbT) measured at various CBF levels (see Equation 3) within the specified bins. The CBF bins are labeled by their central numbers (e.g., CBF Level 0.8 spans the range of CBF levels from 0.75 to 0.85), and the CBF Level 1 indicates the preischemic responses. Here, the CBF bin 0.9 is omitted since the temporal plots look very similar to the preischemic responses. The error bars indicate the standard errors of these averages, and the 4-second forepaw stimulus is indicated in the panels by a thick black line (omitted from CBF Level 1 panel for readability).