<div dir="ltr"><div><div><div><div>Thanks for your answer,<br><br></div>Is there anyway to use the dSPM or sLORETA algorithm and still be able to reliably apply the fMRI prior weighting constraints?<br></div>Because it seems to me that, with fMRI constraints, WMNE algorithm performs well with reasonable, as expected results, but after the noise normalization steps (dSPM/sLORETA), the results become unexpected, if not inaccurate.<br>
</div>Thank you MNE users<br><br></div>Thinh Nguyen<br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Jun 26, 2014 at 10:01 AM, Alexandre Gramfort <span dir="ltr"><<a href="mailto:alexandre.gramfort@telecom-paristech.fr" target="_blank">alexandre.gramfort@telecom-paristech.fr</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">hi Thinh,<br>
<br>
real quick and hand waving:<br>
<br>
dSPM / sLORETA use scaling to downweight locations<br>
where the noise is strong / highly amplified. This amplification<br>
factor is proportional to the fMRI weight. So if you normalize<br>
by division you pretty much cancel the main effect of the fMRI weight.<br>
<br>
HTH<br>
Alex<br>
<div><div class="h5"><br>
<br>
<br>
On Wed, Jun 25, 2014 at 10:42 PM, Thinh Nguyen<br>
<<a href="mailto:thinhnguyen0405@gmail.com">thinhnguyen0405@gmail.com</a>> wrote:<br>
> Hi MNE users,<br>
><br>
> I'm currently trying to applying a a prior source constraints via the fMRI<br>
> weighting file. But according to MNE documentation:<br>
> "It turns out that the fMRI weighting has a strong influence on the MNE but<br>
> the noise-normalized estimates are much less affected by it."<br>
> (<a href="http://martinos.org/mne/stable/manual/mne.html#cbbdijhi" target="_blank">http://martinos.org/mne/stable/manual/mne.html#cbbdijhi</a>)<br>
> Can anyone please explain to me why this is such a case, maybe in both<br>
> mathematical and intuitive sense. Thank you very much in advance.<br>
><br>
> Regards,<br>
> Thinh Nguyen<br>
> Research Assistant<br>
> University of Houston - Biomedical Engineering department<br>
><br>
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