That's actually quite a good idea. Should've thought of that myself :-)
Cheers,
Cornelius
On Sat, Oct 8, 2011 at 11:01 PM, Benjamin Kay <[log in to unmask]> wrote:
> You could to two separate tcICAs and compare the groups visually as an
> exploratory measure. Then, if you are satisfied that your ICs of interest are
> similar enough, you could go ahead with the combined tcICA and dual
> regression. Otherwise, short of graph theory, I'm not aware of a better
> statistical tool for your situation. I'm curious what others think about how
> robust dual regression is in your situation.
>
> On Saturday, October 08, 2011 16:45:44 you wrote:
>> Hi, thanks for your reply. Yeah, of course, this would work
>> (hopefully). The reasons for perhaps using two tcICAs are that a) I
>> only have half the number of patients compared to controls (20 vs
>> ~40), and there has been some dispute about whether this might throw
>> off balance across groups. Plus, b) the patients are quite severely
>> ill, so their RSNs might differ a lot (at least, that's what we
>> expect), and I am not exactly sure what a tcICA might make of that
>> when both groups are in the same analysis. What do you (and others)
>> think?
>> Cheers,
>> Cornelius
>>
>> On Sat, Oct 8, 2011 at 10:22 PM, Benjamin Kay <[log in to unmask]> wrote:
>> > As you explained, running dual regression on two different sets of ICs
>> > presents a challenge. Why not do tcICA on data from both groups,
>> > together, and then launch your dual regression from there?
>> >
>> > On Saturday, October 08, 2011 16:16:41 you wrote:
>> >> Hi,
>> >>
>> >> it has been suggested on the list to generate a set of RSNs from the
>> >> "healthy" population and to run it against the "patient" group when
>> >> large differences are expected. That's what I am trying to do because
>> >> I have reason to assume so.
>> >> I imagine this means running tcICA on both the control and the patient
>> >> group separately and then (when calling the dual_regression script)
>> >> using melodic_IC.nii.gz from the control.gica on the .filelist from
>> >> the patient.gica - is that right? But how can I include possible
>> >> additional/specific artefacts represented in the patient
>> >> melodic_IC.nii.gz that might not necessarily be present or identical
>> >> in the control group in the analysis? Fslmerge the ICAs of interest
>> >> from the control melodic_IC into the patient melodic_IC and use that
>> >> instead (and possibly throw out ICAs from the patient melodic_IC that
>> >> look similar beforehand)? Did anyone do this succesfully and can
>> >> advise?
>> >> Thanks a lot,
>> >> Cornelius
>
--
Dr. med. Cornelius J. Werner
Department of Neurology
RWTH Aachen University
Pauwelsstr. 30
52074 Aachen
Germany
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