It is just a standard multiple regression analysis where all regressors
are fit simultaneously. One weight does not include that of another weight.
doug
On 3/12/14 5:16 AM, L. Schweren wrote:
Dear FreeSurfer experts,
I am attempting to disentangle the effects of different features of
pharmacological treatment on cortical thickness.
I am running glmfit from the commandline, with multiple covariates
(a.o. Z_Age, Z_TreatmentDuration and Z_StartAge) in the fsgd-file.
These covariates are correlated up to approximately 0.6 , which to my
understanding is not ideal yet not inducing collinearity. Running
glmfit, I do not get any errors such as ill-designed matrix or so.
My question regards the way the different regression weights are
calculated in each voxel. If I test the variance in CT of voxel A
explained by for example TreatmentDuration, and part of the variance
in voxel A is explained by both TreatmentDuration and StartAge, will
the regression weigth of TreatmentDuration than include the part that
is also explained by StartAge? Or are all other covariates first
"regressed out" of the variance, such that the variable I test can
only explain the variance that was not explained by any of the other
covariates?
Thank you very much, your help is very much appreciated!
Best wishes,
Lizanne
_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
_______________________________________________
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.
