[FieldTrip] magnetic dipoles

[Robert Oostenveld]

Hi Borna,

For MEG the FieldTrip forward and inverse functionality will make use of a magnetic dipole if you specify the headmodel (or “vol” structure) as

headmodel = [];
headmodel.type = ‘infinite’;

Important is that the sensor array should be detected as a “meg” sensor array, i.e. it should have coilpos, coilori and tra fields. See http://www.fieldtriptoolbox.org/faq/how_are_electrodes_magnetometers_or_gradiometers_described <http://www.fieldtriptoolbox.org/faq/how_are_electrodes_magnetometers_or_gradiometers_described> for that.  

If the sensors describe eeg electrodes, the forward computation with the same headmodel specification will be for an electric dipole in an infinite conductive medium.

Hope this helps,
Robert

PS if would actually be good to document the magnetic dipole on http://www.fieldtriptoolbox.org/faq/what_kind_of_volume_conduction_models_are_implemented <http://www.fieldtriptoolbox.org/faq/what_kind_of_volume_conduction_models_are_implemented> Feel free to edit that page and add the information from this mail.



> On 20 Oct 2016, at 02:35, Borna, Amir <aborna at sandia.gov> wrote:
> 
> Hi,
> 
> I have a question regarding source localization of head coils; it seems the fieldtrip’s tutorials are directed toward localizing “current dipoles” as opposed to “magnetic dipoles”, e.g. head localization coils. So how should I setup the configuration (headmodel, vol, etc.) for source localization (and simulation) of magnetic dipoles? Thank you for your help in advance.
> 
>  
> 
> Best,
> 
> Borna.
> 
> SNL
> 
>  
> 
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