Thanks a lot for your quick answer. In the aseg, the gray matter in this region is not labelled. I've attached two cases of such error in the participants.

In the first participant (S156), the cc seems to be O.K., yet the gray matter is not labelled. I tried to correct the aseg but the segmentation doesn’t change: indeed, the modification does not seem to have been taken into account after the recon-all -noaseg, even after modifying both the aseg and the aseg.presurf.

In the second participant (S115), the cc is mislabelled, and it’s probably what causes the error of segmentation and gray matter labelling.

All in all, I have two patterns of error. Do you have any modifications in mind that could solve these issues?

On Feb 24, 2019, at 8:14 PM, Bruce Fischl <fischl@nmr.mgh.harvard.edu> wrote:

Hi Maxime

what does the aseg look like in that region? The pial surface gets "frozen" adjacent to the cc (so it is fixed to be in the same location as the white). Maybe the cc if off by a bit?

cheers
Bruce
On Sat, 23 Feb 2019, Maxime Perron wrote:

External Email - Use Caution
Dear Freesurfer experts,

I use Freesurfer 6 on macOS Sierra 10.12.6. I noticed a potential error in some of my participants. In
fact, there seems to have an error in the segmentation of gray matter. You will find attached pictures
of the segmentation. I am wondering if it is an error and if anyone has any idea to fix it. I think it
affects the surfaces.

Thank you,
Maxime Perron

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