[FieldTrip] Performing group analysis with whole brain connectivity

[Zink, Nicolas]

Dear Fieldtripper community!

I am currently working on a pipeline for EEG data to perform network analysis with Fieldtrip (well documented example in http://www.fieldtriptoolbox.org/tutorial/networkanalysis). So far, I have successfully adapted the MEG example for performing EEG network analysis with single subjects, which seems to produce reliable outcomes.

However, I want to perform a group analysis where I want to plot the connectivity of networks from group A with group B. Therefore, a prerequisite is to compute group averages from source data.

So my question is: Has anyone performed a connectivity and/or network analysis on a group level?

Here is what I have tried out that did not work:

·         Calculating the group mean of the source data with ft_math after using ft_sourcedescriptives, which caused problems for the connectivity (ft_connectivityanalysis) and subsequent network analysis (ft_networkanalysis)

·         I also tried ft_sourcegrandaverage, which also is not capable to provide enough (single) trial information for the following connectivity analysis steps.

At the end I took preprocessed EEG data for each subject in my groups and put them together in one dataset using ft_appenddata, which produces some plausible data. Using this strategy, I tricked the algorithm, so it operates the data thinking it is a single subject. I am concerned whether this could cause methodological issues. Is there another (easier) way to do this?

Can anyone give me some advice which strategy would be best to calculate the group mean and why?

Cheers and thanks in advance
Nicolas Zink
wissenschaftlicher Mitarbeiter
Universitätsklinikum Carl Gustav Carus
Klinik für Kinder- und Jugendpsychiatrie und -psychotherapie
Schubertstraße 42
01307 Dresden
Tel. +49 (0)351 458-2303

Universitätsklinikum Carl Gustav Carus
an der Technischen Universität Dresden
Anstalt des öffentlichen Rechts des Freistaates Sachsen
Fetscherstraße 74, 01307 Dresden
http://www.uniklinikum-dresden.de<http://www.uniklinikum-dresden.de/>
Vorstand: Prof. Dr. med. D. M. Albrecht (Sprecher), Wilfried E. B. Winzer
Vorsitzender des Aufsichtsrates: Prof. Dr. med. Peter C. Scriba
USt.-IDNr.: DE 140 135 217, St.-Nr.: 203 145 03113

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