Volume conduction model for EEG DICS beamforming
Jared Van Snellenberg
jaredvs at GMAIL.COM
Fri Jun 29 03:31:32 CEST 2007
Hi all,
I'm currently working on a few DICS beamforming analyses for an EEG dataset
I have, and I have a couple of questions regarding obtaining a good volume
conduction model to include in the cfg.vol input to sourceanalysis.
I do not have MRIs or headshape information for my subjects, but of course
I have electrode position information in spherical coordinates (stored in
an elec structure imported from a BESA .elp file).
It's not clear to me how to generate a volume conduction model with this
information, so any guidance here would be greatly appreciated. Ideally, I
would like to use a 4-shell model. The FIELDTRIP documentation indicates
that this model is implemented, but I can not seem to find the relevant
function (and prepare_singleshell requires headshape information or an nx3
sensor array--I presume in grid coordinates--that I do not have). Finally,
all of the relevant prepare_XXX functions seem to indicate that they are
specifically for MEG data, so I wanted to make sure that whatever approach
I use is appropriate for EEG electrodes rather than MEG sensors.
Thank you very much,
Jared Van Snellenberg
Social Cognitive Affective Neuroscience Unit
http://scan.psych.columbia.edu
(212) 854-7858 p
(212) 854-3609 f
Department of Psychology, Columbia University
406 Schermerhorn Hall
1190 Amsterdam Avenue, Mail Code 5501
New York, NY 10027
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