To FSL experts.
I have got T1 data and a test score for several elderly subjects. We collected the test score and re-scanned them 1 year later. I am interested in the relationship between the change in test score between scans and GM change as a result of ageing.
I ran VBM to create a mask which is the GM change between scan 1 and scan 2 (as is here https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind1008&L=FSL&P=R8137&I=-3&d=No+Match%3BMatch%3BMatches ) so this overcomes the issue of repeated measures in randomise I think. What I am struggling with is the appropriate model and contrast for the next step.
Can someone offer some help with the design matrix please? I know that I would have age as EV1 and test score change as EV2, but I’m not sure whether to demean these, and what contrast will answer my question. Please help. I have spent so much time reading through the jisc mailing list to find a solution but I’m stuck. Sorry if this is easy.
Thanks
Sam
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