  In this work, we describe in more detail how to perform fMRI group analysis
using inputs from modeling fMRI signal using Matrix-Variate Dynamic Linear
Models (MDLM) at the individual level. After computing a posterior distribution
for the average group activation, the three algorithms (FEST, FSTS, and FFBS)
proposed from the previous work by Jim\'enez et al. [2019] can be easily
implemented. We also propose an additional algorithm, which we call
AG-algorithm, to draw on-line trajectories of the state parameter and therefore
assess voxel activation at the group level. The performance of our method is
illustrated through one practical example using real fMRI data from a
"voice-localizer" experiment.
