[FieldTrip] phase difference between sources
Jan.Hirschmann at med.uni-duesseldorf.de
Jan.Hirschmann at med.uni-duesseldorf.de
Thu Sep 6 15:06:02 CEST 2012
Dear fieldtrip experts,
I was wondering how to get the mean phase difference between two sources A and B at a particular frequency f (mean across data segments). My idea was to use dics and to say cfg.refdip=A and cfg.keepcsd='yes'. Then I would get C, the cross spectral density between A and B, which is a 3x3 matrix with complex entries. Joachim Gross wrote that one could estimate csd in the dominant direction as the trace of C. So I guess I could get the phase difference by angle(trace(C)). Is this correct? If I wanted to use SVD to estimate the dominant direction instead of the trace, how would I get the phase difference then? And finally, if I wanted to have coherence not with the dipole orientation that maximizes power but with the orientation that maximizes phase difference, how would that work?
Thanks for any remarks!
Jan
--
Jan Hirschmann
MSc Neuroscience
Institute of Clinical Neuroscience and Medical Psychology
Heinrich Heine University Düsseldorf
Universitätsstr. 1
40225 Düsseldorf
Germany
Tel: +49 (0)211 81 18415
Fax: +49 (0)211 81 19033
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