Peigneux-Komaromi,
> I want to correlate 17 PET scans with corresponding behavioral score
> using the non parametric approach proposed in Snpm96, but I encounter
> some trouble with variance smoothing.
>
> I use snpm plug-in "SingleSub: Single Covariate of interest". After
> scans selected and covariate entered, I have the following messages
> (with my answers):
You have found a bug that arises when doing volumetric smoothing
(z-smooth > 0) and when analyzing more than 16 images.
The key is this combination of messages:
> ======================================================================
> FWHM(mm) for Variance smooth
> ======================================================================
>
> FWHM(mm) for Variance smooth (Default: 0 ) : 10 10 10
> WARNING: Working volumetrically because of smoothing in z (10),
> but more than 17 scans analyzed.
> May run outof memory.
...and then when you go to run...
> ??? Error using ==> spm_snpm
> Cannot z-smooth variance in non-volumetric mode
A one line omission in the file spm_snpm_ui.m caused the problem.
After we issue the warning about volumetric smoothing, we omitted
the command to switch on volumetric mode (line 242).
Download the latest version from the website:
http://www.fil.ion.ucl.ac.uk/spm/snpm/#spm_snpm_ui.m.96b
-Tom
-- Thomas Nichols -------------------- Department of Statistics
http://www.stat.cmu.edu/~nicholst Carnegie Mellon University
[log in to unmask] 5000 Forbes Avenue
-------------------------------------- Pittsburgh, PA 15213
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