Previous studies on event-related functional magnetic resonance imaging (ER-fMRI) experimental designs are primarily based on linear models, in which a known shape of the hemodynamic response function (HRF) is assumed. However, the HRF shape is usually uncertain at the design stage. To address this issue, we consider a nonlinear model to accommodate a wide spectrum of feasible HRF shapes, and propose an approach for obtaining maximin effcient designs. Our approach involves a reduction in the parameter space and an ecient search algorithm. The designs that we obtain are much more robust against mis-specifed HRF shapes than designs widely used by researchers.
Robust Event-Related FMRI Designs Under A Nonlinear Model