3) Perform Volume Registration using AFNI 3dvolreg
        3dvolreg -base <bfile> -prefix <pname> <target file>

Base dataset:Target datasets:
mprage1_n3+origmprage2_n3+orig mprage3_n3+orig mprage4_n3+orig
Volume
preprocessing
Segmentation
Tessellation
Inflation
Manual Editing
Re-inflation
Fix topology
Final Surface
Volume/Surface
postprocessing
Cutting &
Flattening
Prefix for output datasets:
mprage2_n3vr  mprage3_n3vr mprage4_n3vr