Hi, you could try including average cortical thickness over the entire > hemisphere as a covariate. This was Mike Harms' suggestion, and I think a > good one.
why is it a good one? for cortical thickness: i'm not so sure. my 2 cents (and i may be wrong!): - controlling for intracranial volume is done to remove differences due to overall size variability. - the relationship between thickness and size is much less strong than between volume and size (or surface and size). - suppose your groups differ in mean thickness, if you would like to include mean thickness as a covariate in a mapping study (vertex-wise comparisons) of cortical thickness you would have to show that the group-difference in mean thickness is due to an effect that's spread out over the whole cortex (an overall effect, not localized), otherwise the mean thickness covariate is not a good estimator of the overall size factor that you'd like to remove. check Peter Kochunov's recent publications on this. -joost cheers > Bruce > > > > On Thu, 8 Apr 2010, Liukarl wrote: > > >> Hello, Freesurfer experts: >> >> I noticed for analyzing the results from autorecon2, the intracranial >> volume are controlled as covariate in some publications. Is there any >> corresponding covariate for cortical results from autorecon3, cortical >> thickness, surface, and volume? >> >> In my current study, there are two group: one is a group with less optimal >> developmental environment and the other is control. I noticed that without >> any covariate, the r square from cortical measure and group variable was >> really low, only accounting for 2%. Is any standard way to analyze the >> cortical data? >> >> >> Thanks! >> >> Karl >> _________________________________________________________________ >> MSN十年回馈，每位用户可免费获得价值25元的卡巴斯基反病毒软件2010激活码，快来领取！ >> http://kaba.msn.com.cn/?k=1 > > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > The information in this e-mail is intended only for the person to whom it > is > addressed. If you believe this e-mail was sent to you in error and the > e-mail > contains patient information, please contact the Partners Compliance > HelpLine at > http://www.partners.org/complianceline . If the e-mail was sent to you in > error > but does not contain patient information, please contact the sender and > properly > dispose of the e-mail. > >
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