System identification, encoding models, and decoding models: a powerful new approach to fMRI research (Gallant, Nishimoto, Naselaris & Wu, in Visual Population Codes, MIT Press, 2012)
Most fMRI experiments employ a deductive approach in which a specific hypothesis governs selection of a narrow range of stimulus and task parameters. This chapter explains an alternative approach called system identification (SI). The goal of SI is to construct an explicit encoding model for each voxel that predicts responses to any arbitrary input. This approach is much more efficient and much more powerful than the conventional approach.