Hi everybody!
I am totally green to MELODIC and I would like to have some hints.
I have performed a longitudinal study with three groups. Each group received a resting state fMRI before and after a treatment. Our hypothesis is that the three different treatment affect the resting state functional connectivity in a different way. So what I thought to do is performing MELODIC (multi-sessions temporal concatenation) on my functional data, in order to perform dual regression as a second step and comparing the three groups.
Here come the questions:
1) Since I have two session for each subject, that are identical as for what the subject does (i.e. nothing) but should differ because of treatment, what should I do ? Should I nonetheless temporally concatenate the two sessions and feed one 4D image for each subject ? Should I feed the two sessions as separate images (i.e. enter subjects x 2 images) ?
2) I thought that I should run melodic on the whole sample, without dividing it by group. Am I right ?
3) Related to question 1. If I feed MELODIC with the temporally concatenated session for each subject, how I can get back and observe the effect of time ? And if I feed MELODIC with two sessions for each subjects separately, can I calculate then a delta between the component at time 1 and time 2 and use this delta for testing differences in the group using randomise ?
I hope that my questions are clear enough.
Thank you in advance
Alain