Combined Analysis of Breath Hold and Post-Stimulus Undershoot Signals

Todd B. Harshbarger¹, Allen W. Song¹

A previous study indicated that diffusion weighting can be used to separate regions based on the characteristics of the post-stimulus undershoot. These regions were hypothesized to contain separate vascular contributions, and indicated an undershoot metabolic origin. Here, we use a breath hold task (BHT) to further investigate the vasculature within these regions. The BHT produces a vascular response without a metabolic response, and is used in calibrated BOLD methods to even out activity based on varying vasculature. We found regions which, based on undershoot characteristics, are hypothesized to contain larger vessels do show larger breath hold responses, corroborating previous results.