Real-time measurements of pO2 gradients, CBF, and CMRO2 in the rat brain during functional activation

We present a novel method for real-time measurement of the oxygen (pO2) gradients between intra- and extra-vascular compartments in rat brain cortex during functional activation. This information, obtained in parallel with measurements of cerebral blood flow (CBF), permits determination of absolute cerebral metabolic rate of oxygen (CMRO2). The timing of pO2, CBF, and CMRO2 responses is captured with high temporal resolution (~7 Hz). We discuss these results in the context of physiological models that connect oxidative metabolism to neuronal activation.