¥Data Preparation: Smoothing
HSpatial variability of both
FMRI and the Talairach transform can result in little or no overlap of
function between subjects.
åData smoothing is used to
reduce this problem.
íLeads to loss of spatial
resolution, but that is a price to be paid with the Talairach
transform
åIn principle, smoothing
should be done on time series data, before data fitting (i.e.,
before 3dDeconvolve or 3dNLfim, etc.)
íOtherwise one has to decide
on how to smooth statistical parameters.
ÈIn
statistical data sets, each voxel has a multitude of different parameters
associated with it like a regression coefficient, t-statistic, F-statistic,
etc.
ÈCombining
some statistical parameters across voxels might result in parameters with unknown
distributions
íBlurring is done using 3dmerge with the -1blur_fwhm option
íBlurring on the surface is
done with program SurfSmooth