Dear Marco,
It does the same thing. It's actually described as a comment in
spm_peb_ppi.m:
% if tmpw==0 then don't include the column in the
% design. This takes care of the possibility that the
% user would select to include the column but then give
% it a 0 weight.
Best regards,
Guillaume.
On 16/11/16 16:00, Marco Caviezel wrote:
> Dear SPMers,
>
> I’m trying to do a PPI analysis of an event-related design.
> After clicking on the “PPIs-Button”, I specified the SPM file on single subject level and chose psychophysiologic interaction.
> As physiological variable I have chosen my VOI-file I generated before.
> Now I can chose which contrasts from the SPM-file, I would like to include in my PPI model.
> My question is, if it makes a difference if I click “No” for a specific contrast or if I click “Yes” and set the contrast weight to 0?
> Until now I couldn’t find any recommendations which is the better way for calculating a PPI model.
>
> Is there anybody who has an idea about this issue?
>
> Thank you and best regards
>
> Marco
>
--
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
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