Laura M. Parkes1, Guy Lumley2, Rafat S. Mohtasib2, Hedley Emsley3, Jonathan A. Goodwin2
1Imaging Sciences and Biomedical
Engineering, University of Manchester, Manchester, UK; 2Magnetic
Resonance and Image Analysis Research Centre, University of Liverpool, UK; 3Department
of Neurology, Royal Preston Hospital, UK
Calibrated fMRI allows quantitative estimates of the relative changes in cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow that accompany neural activation. In this study we consider differences in these measures between a young and a healthy old group during a cognitive Stroop task using hyperoxia calibration. The BOLD response to hyperoxia was reduced in the older group, leading to a reduction in calibration constant A in all regions which we believe relates to a reduction in blood volume. CMRO2 was also lower in all regions in the older group, despite increased BOLD response in frontal regions.