¥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