[FieldTrip] simulating a dipole with a real headmodel and using DICS to locate it misplaces the source
Thomas Hartmann
thomas.hartmann at th-ht.de
Fri Feb 24 18:33:52 CET 2017
hi,
i wanted to see whether i can simulate a dipole with the data provided
by the tutorial and use the DICS beamformer to see where the source gets
projected.
the code i used is in the attached file.
it expects the data you can download from here:
ftp://ftp.fieldtriptoolbox.org/pub/fieldtrip/tutorial/beamformer/
in a folder called "beamformer".
the puzzling thing is that i do not seem to manage to have it project
the sources anywhere near to the original dipole in the simulation. the
center of the head bias come out nicely if neither baseline correction
or NAI calculation is used. i also checked whether the the coordinate
system of the volume and the grid i generate match. i also checked
whether the chosen dipole shows up at the correct location when i plot
it on the head model.
so, my question is: what do i not get here? maybe there is something
wrong with my script? maybe ft_dipolesimulate is not supposed to be used
that way?
i would really appreciate any suggestions.
best,
thomas
ps: i also tried with eloreta and a simple dipole fit. the results look
slightly different but not really any better...
--
Dr. Thomas Hartmann
Centre for Cognitive Neuroscience
FB Psychologie
Universität Salzburg
Hellbrunnerstraße 34/II
5020 Salzburg
Tel: +43 662 8044 5109
Email: thomas.hartmann at th-ht.de
"I am a brain, Watson. The rest of me is a mere appendix. " (Arthur Conan Doyle)
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