-------------------------------------------
entry variable: $kfwhm -- full width halfmax 3D kernel
-------------------------------------------
default: 1.5 pixels

The "fwhm:" field sets the width of the 3D
Gaussian smoothing kernel applied to the
functional statistics, after they have been
upsampled to pixel resolution of structural
underlay (1x1x1mm or 0.5x0.5x0.5mm).  Thus, the
default setting of fwhm (1.5 pixels) is 1.5mm for
a 256^3 underlay, but 0.75mm for a 512^3 underlay.

If the FWHM of the Gaussian kernel is increased,
the kernel cell size (unlabeled entry to left,
also in pixels) should be increased, too, to
avoid truncating the edge of the Gaussian (kernel
cells should be ~3x fwhm pixels).
