[FieldTrip] Magnetometers and gradiometers for source localisation

[Casper Kerren]

Hi,

I am currently source localising an effect using LCMV on Elekta MEG data. I have both gradiometers and magnetometers and have until recently treated these as the same when preparing the leadfield. However, after having had discussions with my colleagues about the different units and strength for grads and mags, we are hesitant as to what might be the best way of selecting channels. I have searched the fiedltrip mailing list, and have found some answers, but nothing that I can say is very convincing. Could someone point me in the right direction regarding this? Perhaps someone who has done some checks on using both grads and mags and using only grads or mags. We are interested in a deeper source, and naively thought that magnetometers would be necessary to include. However, is this just as I say: naïve?

In the ft_prepareleadfield function I can see that gradiometers is the only channels that are thought of being included, so does fieldtrip actually expect us to exclude magnetometers?

Kind regards,

Casper Kerrén, PhD student
School of Psychology
College of Life and Environmental Sciences
University of Birmingham
Edgbaston
Birmingham B15 2TT
e-mail: cxk699 at student.bham.ac.uk<mailto:cxk699 at student.bham.ac.uk>



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