Dear Pia,
I struggle to read your screen shot: could you send me a higher
resolution one as well as the corresponding SPM.mat?
Many thanks,
Guillaume.
On 07/11/16 12:00, Pia Rotshtein wrote:
> Dear Experts,
>
> We are running a VBM study. We used peak-level cluster of p <.001
> uncorrected, and 50 voxels.
>
> What we found puzzling in the results table (which we never observed
> before) is that sometime smaller clusters are denoted as more reliable
> than larger clusters.
>
> I took a screen shot to demonstrate the point:
>
>
>
> So you would see that clusters with 200 (highlighted cluster), or with
> 366 (first cluster) voxels are reliable at FWE and also as uncorr, while
> clusters with 507 voxels are not (the cluster just above the highlighted
> one).
>
> So Our questions:
>
> 1) Has anything changed lately in SPM12?
>
> 2) And also how can that be the case; I though SPM corrected for
> number of expected cluster which should be identical for all clusters in
> a given comparison/model.
>
>
>
> Thank you
>
>
>
> Pia
>
--
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
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