I was able to solve my problem in my earlier email included below. I downloaded a new verison of mris_calc made it executable with chmod +x FILE and then replaced it in the bin folder. I included this response in case anyone else runs into the same problem and does a search. ftp://surfer.nmr.mgh.harvard.edu/pub/dist/freesurfer/misc/macos-leopard-intel/

Hello Freesurfer experts,

I am working on a study that wants to compare pre/post cortical thickness on an intervention group and a control group. I am using FS 5.1 on a Mac. I have processed all the recons through the longitudinal stream as described in the wiki/tutorial. However when I go to prepare the data using this command:

long_mris_slopes --qdec ./qdec/long.qdec.table.dat --meas thickness --hemi lh --do-avg --do-rate --do-pc1 --do-spc --do-stack --do-label --time years --qcache fsaverage

It seems to run fine at first but after a minute or so it hits this command and crashes:

mris_calc -o /Applications/freesurfer/subjects/SPIN073/surf/lh.long.thickness-spc.fwhm0.mgh ./tmp-SPIN073_lh_thickness_igG3e9/beta1.mgh div ./tmp-SPIN073_lh_thickness_igG3e9/beta0.mgh

It prints: ERROR 1 : mris_calc compute sym. pct. change (spc) problem?

And then returns to my command prompt.

I searched online and found someone last year asked the same question here:

https://mail.nmr.mgh.harvard.edu/pipermail//freesurfer/2011-September/020311.html

However the response links to an updated version of mris_calc but when I click the link it says I do not have permission the access.

Thanks for any help in advance.

-Andrew