• spatialsmooth-sess -s [subject] -df sesspar -i fmc -o fmc[smX] -fwhm [fwhm]

For a VolumeAnalysis [fwhm]=8 or 6 is typical. For a SphericalAnalysis, it is common to apply minimal smoothing ([fwhm]=2) in VolumeSpace and then apply additional smoothing in SphericalSpace using FsFastSphericalSmooth. See Smoothing for a discussion of the effects of smoothing.