Hi all,
1. How MELODIC decides that after thresholding the spatial maps which brain regions are red/active and which are blue/deactive? As far as I know multiplying a component by -1 does not change the independence of that component. So if we multiply the time course of a component by -1 then the red and blue colours will change (Red-> blue and Blue-> red). In my opinion using ICA and classifying the ICs into task-relevant source groups by a correlation threshold criterion, we can't interpret any region seen on a "task-related spatial map" with red as activation of that region. Am I right? How can we interpret the regions seen on these "task-related spatial maps" in a meaningful way?
2. How can we interpret the results, if we use Tensor ICA and perform a post-hoc regression analysis specifying a session/subject design matrix?
For example: I have two groups and I do fMRI measurements using the same stimuli for both group. I run tensor ica and post-hoc analysis to address which components are those that are more typical for one group than for the other. How can I interpret these components and the active/deactive regions seen on the spatial maps of these components.
Thank you,
Gábor
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