Spatial Sparsity

Neighboring voxels are encouraged to share activation patterns while sparse variable selection is preserved. BNR activation maps showed stronger spatial coherence than ISC maps in the movie-viewing analysis. The checkerboard study found BNR maps had somewhat stronger spatial coherence than GLM maps. Spatial dependence is modeled through local shrinkage scale parameters. Voxel neighbors are defined by shared faces, giving each three-dimensional voxel at most six neighbors.