[FieldTrip] DICS with rawtrial='yes'

[Muller, Nadia]

Dear all,

I am trying to beam single trials into source space using a DICS filter and the following code.

cfg=[];
cfg.method='dics';
cfg.grid=grid_ind;
cfg.vol=hdm;
cfg.grid.filter=alldics.avg.filter;% common filter
cfg.dics.lambda='5%';
cfg.channel=channs;
cfg.frequency=13;
cfg.grad=data.grad;
cfg.keeptrials='yes';
cfg.rawtrial='yes';
dics=ft_sourceanalysis(cfg,pow);%pow contains csd of singletrials (only one condition)

I would suppose that the average of the rawtrials (obtained by ft_soucredescriptives([],dics) or by averaging power of single trials myselves) should be comparable to the output of dics with rawtrials='no' (and also keeptrials='no').

However this is not the case (the averaged raw trials have a 30-60% bigger amplitude compared to the average values obtained from dics without rawtrial='yes'). Am I misunderstanding something here? Or could it be that I use wrong parameters for beaming single trials?

Thanks for any advice!

Best,
Nadia

Dr. Nadia Müller
CIMeC - Center for Mind/Brain Sciences
Università degli Studi di Trento
via delle Regole, 101
Mattarello (TN) - ITALY
e-mail nadia.muller at unitn.it<mailto:nathan.weisz at unitn.it>
http://sites.google.com/site/obobcimec
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