Figure 9From: Relationship between oxygen supply and cerebral blood flow assessed by transcranial Doppler and near – infrared spectroscopy in healthy subjects during breath – holdingNIRS signals and VMR pattern for subject A. Time course of the O2Hb and CO2Hb concentration signals for subject A (healthy current smoker) during BH (left panel) and bidimensional VMR pattern (right panel). The signals reveal an uncompensated increase of the CO2Hb level, that determines a VMR pattern always out of the two bisectors region. Also, the onset of VMR is delayed and the VMR pattern never reaches a plateau condition.Back to article page