Abstract #0541

Liu H, Shih Y, Chao T, Chen C, Chung H, Liu Y, Juan C, Ko C, Wang C

The neuron-activity related BOLD signals (fBOLD) could be interfered by the BOLD signals coming from the inhaled CO2 (hBOLD). Prior studies have focused on the relation between the fBOLD and hBOLD, however, leading to discrepant results. We hypothesize that the cerebrovascular reserve might be limited by original global vasodilatation at high inspired CO2 fractions, restrict further neuroactivity-related vasodilatation, and then attenuate the BOLD signal change. In this study, we broaden the range of CO2 concentration from room air to 7% and extend the experiment duration to cover the transient and steady states BOLD responses.