Sorry, this looks like it may have become unlinked from the original posting (maybe because my response was to a pretty old thread?). In any case, here's the context:
Hi,
You don't have to worry about this.
There is no orthogonalisation because the results that you
get with contrasts that exclude the confounds (as they should)
are *exactly* the same whether you orthogonalise the main
EVs wrt the confounds or not. Hence there is no reason to
have this option as it changes nothing of interest.
All the best,
Mark
On 2 Jul 2010, at 20:44, Mona Maneshi wrote:
> Dear FSL Experts,
> Hi,
>
> I am using FEAT to do seed-based functional connectivity analysis. I
> need to add some confounds to my GLM. Because of the large number of
> confound regressors that I have, I need to use "Add additional
> confound EVs" option in "Stats" tab.
> 1) I am wondering if my regressor of interest defined in the "Full
> model setup" (i.e. the averaged time course over ROI) will be
> automatically orthogonalized with respect to these confounds (I know
> that there is an option to orthogonalize regressors defined in "Full
> model setup" wrt. each other, but what about the EVs wrt. confounds?).
> 2) If not, how can I change the source code to be able to do so?
>
> Thanks in advance and looking forward to hearing from you,
> Mona
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