Hi Lauri, the z we compute is based on the transform from a p-value, not the r-value. This is often referred to as a "pseudo-z". The pseudo-z depends on the degrees of freedom. Now that you mention it, it would probably be better to use the r-to-z transform to compute something closer to a real z. Historically, I wrote the software to compute the pseudo-z a long time ago, the pcc was done just a few years ago.
doug On 05/14/2018 06:26 PM, Lauri Tuominen wrote: > > > Dear freesurfers, > I’m using mri_glmfit to estimate the correlation between a time series from a > seed region and all the voxels in the brain. For one subject I get values in > the pcc.nii.gz around .4 in my region of interest (not seed) but the z-scores > are extremely high, i.e. > 4. Am I doing something totally wrong? My > understanding was that z = arctanh(r). > > Thank you so much again! > Lauri Tuominen > > > _______________________________________________ > 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.
