Hi,
we read the fsl-vbm scripts and wondered why grey matter templates which derive from the subjects will be symmetrical (by right/left-flipping and averaging them)?
\$FSLDIR/bin/fslmerge -t template_4D_GM \$mergelist
\$FSLDIR/bin/fslmaths template_4D_GM -Tmean template_GM
\$FSLDIR/bin/fslswapdim template_GM -x y z template_GM_flipped
\$FSLDIR/bin/fslmaths template_GM -add template_GM_flipped -div 2
In doing so and registering individual GM images to this symmetrical template, we think that hemisphere-dependent information might get lost, and this might bias results - ? Or is there a specific reason for the right/left-flipping?
Thank you in advance for your help!
best, Veronica
|