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Morphologist : GM_thickness
Posted: Mon Jun 26, 2017 1:09 pm
by Mikha
Hi,
It's just a simple question : How is GM_thickness calculated?
M. Azilinon
Re: Morphologist : GM_thickness
Posted: Mon Jun 26, 2017 2:15 pm
by riviere
Hi,
It's just a distance map in the voxels of the GM, going from one interface to the other. As MRI resolution is very low compared to the cortical thickness, they are gross measurement, not very accurate. Then they are averaged for each fold region (which makes them perhaps more robust, but probably not very sensitive to local variations). There are many smarter ways to do it but this one was easy and fast...
Denis
Re: Morphologist : GM_thickness
Posted: Mon Jun 26, 2017 2:56 pm
by Mikha
So, it is what i thought, but can you tell me if it is calculated before or after talairach's normalization?
Thank you,
M. Azilinon
Re: Morphologist : GM_thickness
Posted: Mon Jun 26, 2017 6:07 pm
by riviere
Before. Thickness is calculated in native space (I'm not sure it would make sense in normalized space).
Denis