Hi Darren,
> In order to get the FWHM I typed the following commands
>
> fslmaths grot_tfce_p_tstat1 -ptoz -mul -1 grot_zstat1
> smoothest -z grot_zstat1 -m mask -V?
>
> Is this correct?
>
> However, the FWHM put out by smoothest seems a lot smoother than I would have expected = 24mm. My original images are 1.5x1.5x1.5 mm^3 and were smoothed with an 8 mm Gaussian kernel.
>
> Is this amount of smoothness to be expected?
I think you need to use a raw zstat image (or use ptoz on a non-tfce p image) to calculate the smoothness. I think the tfce process will introduce lots of additional spatial correlation that will increase the apparent smoothness.
Jesper
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