[FieldTrip] Calculation of within-subject interaction

mapaul at uni-osnabrueck.de mapaul at uni-osnabrueck.de
Wed Aug 16 10:53:30 CEST 2017

Dear fieldtrip community,

I found this very helpful tutorial on how to calculate an interaction
effect using a cluster-based permutation:


I have a question regarding this step:

Copy GA11 to GAdiff11_12 and perform the assignment
Copy GA21 to GAdiff21_22 and perform the assignment

I have a full within-subjects design and I was wondering if it matters
which of my factors I define as factor 1 and which as factor 2. In other
words, is there a difference between calculating

GA11.avg - GA12.avg followed by GA21.avg - GA22.avg
as opposed to GA11.avg - GA21.avg followed by GA12.avg - GA22.avg

and then running a permutation test on the differences?

Any help would be greatly appreciated!

Thanks and with best regards,

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