forward modelling without anatomical info
gilbertson.thomas at GOOGLEMAIL.COM
Mon Jan 7 16:59:09 CET 2008
dear jan mathijs,
i have been generating a single shell model from the segmented mri.
the localisation proceedure is for a tactile stimulus so when i see a
contralateral S1 response i have some reason to belive that the algorithm is
making some sense. I get the impression from your reply that there is no
easy way to get around this lack of anatomical data and that i may just have
to go and get the mri's done for this couple of subjects!
thanks for your thoughts on this,
On 1/7/08, Jan Mathijs Schoffelen <jan.schoffelen at fcdonders.ru.nl> wrote:
> Dear Tom,
> As far as I know, the 'ctf-format' standardised mri does not exist.
> Creating an anatomically accurate forward model, while the actual anatomical
> information is lacking, is tricky business. What kind of forward model do
> you actully use? The multiple sphere model based on the ctf-shape files? If
> so, you could try to come up with an 'averaged' multipsphere model (thus
> bypassing the need for a standardised MRI), although this is not
> trial. However, I wonder whether this would yield better results than just
> taking an 'averaged' single sphere model.
> I wonder what you mean by your statement that localisation is much more
> accurate when using ctf-formatted MRIs. Do you know where your activation
> should end up then?
> The function beamformer_pcc is as far as I know still in its experimental
> stage and only for use within the FC Donders Centre. However,
> beamformer_dics shares most of the functionality, but obviously not all of
> 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
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/fcdonders/fieldtrip.
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