Post-hoc selection of dynamic causal models

► New (post-hoc) procedure for approximating the model evidence is applied to deterministic bilinear dynamic causal models for fMRI. ► Post-hoc procedure is based on optimising only the largest model of a set of models. ► Good agreement found between free energy bound and post-hoc approximations to the model evidence and model parameters. ► Post-hoc approach reduces computational time immensely and can be applied to any nested models.