[FieldTrip] DICS: fixed orientation of sources option
andrea brovelli
andrea.brovelli at univ-amu.fr
Thu Nov 15 17:28:46 CET 2012
Dear all,
I have a question regarding the option "fixedori" of DICS (the code
from lines 292 to 306 in beamformer_dics.m).
If I get it right, you implemented the situation when the first
singular value lambda1 is much greater that the second singular value
lambda2 of Cs (Cs is given by eq. 4 of Gross et al., 2001, PNAS).
I checked in my data and this is not the case. Maybe my data is just a
very special case, but I find that the first is a little larger that
the second. Here they are:
lambda1 = 0.5380;
lambda2 = 0.2921;
lambda3 = 0.0000;
After eq. 9 in Gross (2001), it says that if lambda1 >> lambda2 does
not hold, the trace of Cs should be used instead.
So, has it been implemented in Fieldtrip somewhere ? And, if not,
would you know how to do it ?
Thanks a lot
bye
Andrea
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