DICS power

[Cristiano Micheli]

Hi All
I have a problem with DICS's power and my simulations. I simulate an
external virtual channel coupled with MEG activity in a specific frequency
band (around 20 Hz).
I use DICS and submethod 'ref_chan'  and i can localize 1 source (even 2 if
they are distant) but only if I use coherence as a functional parameter and
reducerank=2.
With power i always see a bright spot in the middle of the brain. 
Should i select some options to account for decreased sensors' sensibility
in depth?
Since I used anyway coherence parameter for localization I did not pay
attention to this before but somehow it looks strange to me.
I attach the code and power image.
Regards

    cfg           = [];
    cfg.grid      = grid_; 
    cfg.method    = 'dics';   
    cfg.projectnoise = 'yes';
    cfg.reducerank = 2;
    cfg.lambda    = 0; 
    cfg.refchan   = refch;
    cfg.frequency = 20;
    cfg.hdmfile   = 'myheadmodel.hdm';
    sourcecond    = sourceanalysis(cfg, freqcond);



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