I'm not sure if I'd say it's common, but RFT relies on the image being
sufficiently smooth. From the SPM text, Chapter 18 page 233:
"If the FWHM is small relative to the voxel size, then the Bonferroni
threshold is actually less than the random field one."
Anders Eklund wrote:
> Dear SPMers,
>
> when calculating corrected t-test thresholds, is it common that the
> threshold from random field theory is higher than the threshold from
> Bonferroni correction? In my case (one subject) the random field theory
> threshold is only lower than BC if I use => 8 mm FWHM of smoothing.
>
> /Anders
>
>
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