To me, it makes much more sense to use mean cortical thickness as a covariate for thickness-based analyses.
cheers, Mike H.
Hi Mehul,
the MNI group had an abstract showing that thickness didn't need eTIV correction at HBM a number of years ago, and it has been our experience as well.
cheers, Bruce
On Sat, 31 Oct 2009, Mehul Sampat wrote:
Hi Folks,
If am comparing the mean thickness for certain gyri (pre-central, post-central) in a controls versus patients. I obtain the thickness measurements from lh.aparc.a2009s.stats and rh.aparc.a2009s.stats I was wondering if I need to normalize these thickness measurement with the estimated total intracranial volume (eTIV) ?
Or has anyone reported that the these are independent of eTIV ? If so then as I understand I would only need to account for age and gender in any subsequent analysis using GLM.
Thanks Mehul
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