Hi,
This doesn't sound like too small an ROI; FEAT doesn't implement the
'official' small-volume correction, but in general it doesn't make
much difference anyway. I would go ahead and use this as a pre-
thresholding mask in FEAT. The problem with using randomise in FEAT is
that it doesn't correctly deal with autocorrelations (if this is a
first-level analysis) or full mixed-effects modelling (if this is a
higher-level analysis).
Cheers.
On 15 Feb 2008, at 20:59, Soohyun Cho wrote:
> Hello experts,
>
> I am trying to do small volume correction limiting my search for
> activations within the frontal cortex.
> I made a mask by combining all of the frontal cortex of the Harvard
> Oxford atlas (frontal pole + MFG + IFGtri + IFGop).
>
> If I use this frontal mask as a prethresholding mask within feat,
> would there be any problems? e.g. perhaps this volume is too small
> for Random Field Theory to work properly?
>
> Is it better to use this mask with Randomise for small volume
> correction?
>
> Thank you for your response.
>
> Soohyun.
>
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Stephen M. Smith, Professor of Biomedical Engineering
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FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
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