[FieldTrip] ft_megrealign how to avoid?

[Nenad Polomac]

Dear all,

I have CTF MEG data and I am interested in a gamma band topographies. We
recorded two sessions for every subject. Now I would like to compare grand
averages of these two sessions over all subjects(n=13). Without realignment
these grand average topographies look ok and according to our expectation.
However, I know that it would be reasonable to do realignment of all
datasets (n=13x2) to common template. I have tried that with ft_megrealign
which uses method suggested by Knösche, 2002 and this doesn't work. It
gives me very weird results, meaning that topographies are totally changed
and some new occipital activity emerges. I have plotted single subject head
models(singleshell) together with sensors and they are accurately aligned.
Then I tried different inwardshift options for ft_megrealign and this
didn't bring so much success. So my question is, could I go without the
realignment and what I need to do in order to overcome problem with
realignment?
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