Dear experts,
I have an issue with dual regression stage 2 comparing parameter estimates (PE) and zscore of the same ICA components.
I have identified networks with MELODIC and I want to compare the within-network functional connectivity (wFC) in two groups, let's call them A and B.
I calculated wFC following two approaches:
1. Dual-regression of FSL; 2. Matlab script using the "corr" command.
1. With the first method I obtained connectivity maps for each subject and each network (stage 2 of dual_regression). Let us assume that I am interested in network 1, the result of the ttest done with randomise is a map with all the significant voxels that say "group A >> group B". That is, the average of the individual voxel-maps says group A >> group B.
2. With the second method I obtained a single average number for each subject and each network. Let us assume that I am still interested in Network 1, the test gives me "Group B >> Group A". That is average group B >> group A.
I checked that there were no errors in my scripts or in design, moreover zscore obtained with Matlab gives results similar to the Z maps obtained with dual regression at stage 2, therefore I don't understand how two completely opposite results can come out. Have you any idea?
Thank you very much,
best
Silvia
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