1) I would like to extract only the cortex  cerebrum . So I think I don't need the complete subcortical segmentation ( 20-40 hours).  Do you know a way to segment only cortex or only  ( cortex+ pial ( left/rigt hemispher)?

2) I already try the complete subcortical segmentation ( about 12 hours, with the recon-all command). Do you know a way to extract only the cortex surface from the software? I would like to get the 3D surface mesh  for analysis on Matlab. 

Could you help me, 

Thanks.