Dear SPM/VBM users,
I have performed a VBM T-test identifying an area of grey matter volume difference between two groups. Then I made an analysis of 'structural connectivity' by taking the voxel value at the peak voxel coordinate for each subject and using it as a regressor in a linear regression model for each group. Here I found another area that was positively correlated to the first one. The finding was present in both groups but the cluster differed in size and p-value.
How can i compute the difference in correlation of the two areas between the two groups? Subtraction of betas or thresholded T-maps ? A completely different model?
I am grateful for any suggestions!
/ Carl Johan Ekman
MD, PhD-student
Karolinska Institutet
Stockholm, Sweden
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