Aligning head across runs

[jan-mathijs schoffelen]

Dear Max,

I don't think there is a conceptual objection against building in
support for the NM306 system, although it may be less trivial to do a
combined simultaneous realignment of planar gradiometers and
magnetometers. The choice of the 4 sensors used to compute the
transformation matrix between the 'old' and 'new' sensor positions
seems reasonable to me.
On a side note, doesn't the maxfilter provide you with the possibility
to correct for differences in head position?

Cheers,

Jan-Mathijs

On Jul 15, 2010, at 11:41 PM, Maximilien Chaumon wrote:

> Thank you,
> The layout of our neuromag306 is not supported in ft_megrealign.
> What sensors should I write for constructing the average location of
> the MEG sensors?
> (line 190 and below)
> I have triplets of sensors that match this layout.
> http://fieldtrip.fcdonders.nl/_detail/tutorial/layout/nm306all.png
>
> Figured out these guys might work, but that's just a guess. I've
> done no calculation or anything...
>
>     labC = 'MEG 2111';
>     labF = 'MEG 1011';
>     labL = 'MEG 0141';
>     labR = 'MEG 1431';
>
>
> thanks,
> Max
>
>
> 2010/7/14 jan-mathijs schoffelen <jan.schoffelen at donders.ru.nl>
> Hi Max,
>
> You may want to have a look at the function ft_megrealign.
> Alternatively, you could construct a gradiometer structure which
> contains a meaningful average of the coil positions and orientations.
>
> Cheers,
>
> Jan-Mathijs
>
> On Jul 13, 2010, at 9:28 PM, Maximilien Chaumon wrote:
>
>> Hello fieldtripers,
>>
>> I've read this topic https://listserv.surfnet.nl/scripts/wa.cgi?A2=ind1004&L=FIELDTRIP&D=0&P=4576
>>  which poses the same problem that I'm going to raise now.
>>
>> I have several runs and want to concatenate my data. I understand
>> that I can do ft_appenddata, but that I then loose the sensor
>> positions of the second and subsequent runs.
>> Is there a way to align the head position across runs? Does it make
>> sense to interpolate the data between sensors to align all to the
>> same position?
>>
>> Thanks,
>> Max
>> ----------------------------------
>>
>> The aim of this list is to facilitate the discussion between users
>> of the FieldTrip toolbox, to share experiences and to discuss new
>> ideas for MEG and EEG analysis.
>>
>> http://listserv.surfnet.nl/archives/fieldtrip.html
>>
>> http://www.ru.nl/fcdonders/fieldtrip/
>>
>
>
>
> Dr. J.M. (Jan-Mathijs) Schoffelen
> Donders Institute for Brain, Cognition and Behaviour,
> Centre for Cognitive Neuroimaging,
> Radboud University Nijmegen, The Netherlands
> J.Schoffelen at donders.ru.nl
> Telephone: 0031-24-3668063
>
> ----------------------------------
>
> The aim of this list is to facilitate the discussion between users
> of the FieldTrip toolbox, to share experiences and to discuss new
> ideas for MEG and EEG analysis.
>
> http://listserv.surfnet.nl/archives/fieldtrip.html
>
> http://www.ru.nl/fcdonders/fieldtrip/
>
>
> ----------------------------------
>
> The aim of this list is to facilitate the discussion between users
> of the FieldTrip toolbox, to share experiences and to discuss new
> ideas for MEG and EEG analysis.
>
> http://listserv.surfnet.nl/archives/fieldtrip.html
>
> http://www.ru.nl/fcdonders/fieldtrip/
>

Dr. J.M. (Jan-Mathijs) Schoffelen
Donders Institute for Brain, Cognition and Behaviour,
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands
J.Schoffelen at donders.ru.nl
Telephone: 0031-24-3668063


----------------------------------
The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.
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