Applications of a novel hemodynamic model to functional brain studies with fNIRS and fMRI

We report time-domain applications of a new hemodynamic model by Fantini [1] that yields analytic expressions for signals that are measurable with hemodynamic-based neuroimaging techniques such as functional near-infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI). We show how the model can be used to predict the perturbations in cerebral blood volume (CBV), blood flow (CBF), and metabolic rate of oxygen (CMRO2) that account for the initial dip and post-stimulus undershoot that have been reported in the fMRI and fNIRS literature. Furthermore, we have used data from the literature to perform a comparison between measured fNIRS and fMRI signals and the corresponding signals predicted by the new hemodynamic model. Results showed an excellent agreement between the model predictions and the reported measured data.