Constrained Nonlinear Estimation of FMRI Hemodynamic Response Parameters
We present a constrained nonlinear optimization approach to the estimation of hemodynamic response (HR) shape from fMRI images. The controlled random search (CRS) based strategy limits the HR parameters within a physically/physiologically plausible phase space, and thus may produce more meaningful results than the traditional unconstrained methods. Block-design and event-related fMRI experiments have been conducted to examine the validity of the framework.