Figure 2

Overall diagram of the computational model for neurovascular coupling and BOLD fMRI. It is decomposed into a neurophysiology module (upper dashed box) and a MRI technology module (down dashed box). The linear neurovascular coupling model accounts for the local neuroactivity, blood oxygenation, and cortical vasculature by a spatiotemporal modulation. The complex fMRI dataset is resulted from susceptibility magnetization and intravoxel dephasing (T2* imaging). The complex fMRI dataset can be used for backward mappings as diagrammed by double-directed arrows. It is noted the conventional neuroimaging is diagrammed by an overall backward mapping as diagrammed by a grey double-directed arrow of A ~ NAB on the left-hand side. In this paper, we focus on the mapping from the MR magnitude image to the susceptibility source (as diagrammed by the black double-directed arrow of A~Δχ), and that from the MR phase image to the fieldmap (P~ΔB).