Dear Mark,
Thank you! That makes it clear!
I will give it a try.
Have a nice day
Heidi
================================================
Dr. Heidi Jacobs
Postdoc researcher
Faculty of Health, Medicine and Life Sciences
School for Mental Health and Neurosciences
Division Cognitive Neuropsychiatry and Clinical Neurosciences
Alzheimer Center Limburg
[log in to unmask]
www.maastrichtuniversity.nl
www.heidijacobs.nl
Dr. Tanslaan 12, 6229 ET Maastricht
P.O. Box 616, 6200 MD Maastricht, The Netherlands
T +31 43 38 84 090 F +31 43 38 84 092
================================================
________________________________________
Van: FSL - FMRIB's Software Library [[log in to unmask]] namens Mark Jenkinson [[log in to unmask]]
Verzonden: maandag 7 januari 2013 10:22
Aan: [log in to unmask]
Onderwerp: Re: [FSL] Setting up the correct contrast
Hi,
You will need to split your covariate of interest into 2 EVs, one for each group - with the values demeaned _within_ the groups, and the rest of the EV appropriately padded with zeros. Once you have these two EVs you can test for group differences in the same way as you did with the group means (which I assume were EV1 and EV2 given your contrast example). You need to keep all the other EVs as well (especially the group means) and so you would end up with 6 EVs, not 5.
I hope that's clear.
All the best,
Mark
On 4 Jan 2013, at 14:50, Jacobs H (NP) <[log in to unmask]> wrote:
> Hi FSL people,
>
> I have a question regarding my statistical design that I want to feed into the dual regression (resting state data).
> I have two groups, one covariate not of interest (age), one voxel-based covariate not of interest (grey matter) and one covariate of interest (cognition, continuous).
>
> Just examining group differences would give me this contrast file:
> 1 -1 0 0 0
> -1 1 0 0 0
>
> If I now want to examine group differences in resting state functional connectivity associated with the covariate of interest (cognition), how should I proceed?
>
> Thank you very much!!
> Best
> Heidi
>
>
> ================================================
> Dr. Heidi Jacobs
> Postdoc researcher
> Faculty of Health, Medicine and Life Sciences
> School for Mental Health and Neurosciences
> Division Cognitive Neuropsychiatry and Clinical Neurosciences
> Alzheimer Center Limburg
> [log in to unmask]
> www.maastrichtuniversity.nl
> www.heidijacobs.nl
>
> Dr. Tanslaan 12, 6229 ET Maastricht
> P.O. Box 616, 6200 MD Maastricht, The Netherlands
> T +31 43 38 84 090 F +31 43 38 84 092
> ================================================
