[Freesurfer] make_average_subject

Hi, I have two questions on make_average_subject

1) Why are two sets of surfaces created by the make_average_subject script? What is the difference between e.g. inflated and inflated_avg? Which one(s) should be used for visualization?

2) As far as I understand, make_average_subject is run for visualization purposes only, and the output is not critical for the integrity of the statistical analyses (recon-all does the spherical warping and registration, and t he mris_preproc script makes sure the tesselation is uniform across the data set). So, does it matter if there are defects in the surfaces created by make_average_subject?

I tend to get topological defects in the inflated_avg.

Thank you!