This question is regarding preprocessing/modulating data for longitudinal analysis.
I am examining the differences in grey matter change in two groups between a baseline and a 1 year scan.
I understand that it is unnecessary to modulate images when examining changes over time in a single group, as the Jacobian determinants one uses to modulate are unlikely to change appreciably in any given subject between baseline and Y1.
However, I am also interested in looking at group differences as well as group X time interactions at each time point.
Is modulation necessary/helpful in this situation?
In order to create modulated (non-linear only)grey and white matter images using the VBM8 longitudinal batch (cg_vbm8_longitudinal), is it correct to change lines 95 and 99 from “0” to “2” ?
Kind regards,
Jan-Marie Kozicky; PhD Candidate
University of British Columbia
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