Hi Matthieu

check the aseg at the anterior end of the calcarine and see if it incorrectly labels some voxels there as ventricle. The bit of WM that separates ventricle from calcarine at the posterior horn of the ventricle is thin and sometimes quite dark, and if we lose that the ventricle label can extend incorrectly into calcarine, in which case we think it isn't cortex. If you correct the aseg and rerun from there it should fix it.

cheers Bruce

On Thu, 7 Jan 2016, Matthieu Vanhoutte wrote:

Dear FS's experts,

Projecting volumic data onto native surface (brain mask: "Unknown_S_calcarine_ROI_mask.jpg"), I observed that a thin region in the S_calcarine was set to 0.

I loaded then the inflated left surface and the l.aparc.a2009s.annot ("Unknown_S_calcarine_ROI_annot.jpg") and took into account that this region inside the S_calcarine was set as "unknown" in the parcellation file .

What does it mean and is this possible to correct for this ?

Best regards, Matthieu