Dear Enrico,
> I have been checking the standard preprocessing scripts (prestats) and
> noticed at line 5274 of file featlib.tcl
>
> set smoothsigma [ expr $fmri(smooth) / 2.355 ]
>
> Could you briefly explain where the 2.355 comes from?
it is simply a conversion factor between FWHM and sigma, reflecting
that the user is asked for the smoothness in FWHM whereas the script
that does the actual smoothing expects it in sigma.
> That happens before registration to standard template: does it mean
> that if it was happening after registration to template then: set
> smoothsigma [ expr $fmri(smooth) / 1 ] is valid?
Nope.
Good luck Jesper
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