[Freesurfer] clarification on computation of stats for "unknown" label in aparc

Hello, The "unknown" parcellation in /h.aparc.annot includes vertices of the white/pial surface that correspond to the insula, medial temporal cortex (including hippocampus and amygdala), and the midline.

How are the vertices that "cut" through the hippocampus, amygdala, and midline treated during the computation of the volume and thickness measures in ?h.aparc.stats? Do those vertices contribute to the values computed for the "unknown" region, or are they excluded? (That is, are the values for "unknown" in ?h.aparc.stats derived solely from vertices that are considered to correspond to cortical gray matter, based on the aseg.mgz?)

thanks, Mike H.