Classical and Bayesian Inference in fMRI - Advance Image Processing in Magnetic Resonance Imaging - page 546

FIGURE 17.7 This schematic shows the architecture of the hemodynamic model for a
single region (regional subscripts have been dropped for clarity). Neuronal activity induces
a vasodilatory and activity-dependent signal s that increases the flow f . Flow causes changes
in volume and deoxyhemoglobin ( v and q ). These two hemodynamic states enter an output
nonlinearity to give the observed BOLD response y . This transformation from neuronal
states z i to hemodynamic response y i is encoded graphically by the dark-gray boxes in the
previous figure and that inserted in this figure.