Complex fMRI analysis with unrestricted phase is equivalent to a magnitude-only model.
Due to phase imperfections, voxel time course measurements are complex valued. However, most fMRI studies measure activation using magnitude-only time courses. We show that magnitude-only analyses are equivalent to a complex fMRI activation model in which the phase is unrestricted, or allowed to dynamically change over time. This suggests that improvements to the magnitude-only model are possible by modeling the phase in each voxel over time.
Rowe
Daniel B
DB
Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA. dbrowe@mcw.edu
Logan
Brent R
BR
D000818:Animals; D007091:Image Processing, Computer-Assisted; D016013:Likelihood Functions; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D008959:Models, Neurological; D015203:Reproducibility of Results