Hello,
I am noticing a warning message with mri_glmfit (no voxels in AR1 computation):
Fit completed in 0.06015 minutes Computing spatial AR1 in volume. fMRIspatialAR1(): hit 0 voxels WARNING: no voxels in AR1 computation Residual: ar1mn = (nan,nan,nan) fwhm = (nan,nan,nan) nan Writing results mean maxvox sig=4.90974 F=32.2461 at index 110161 0 0 seed=1257436991 Gender maxvox sig=-2.95011 F=14.2207 at index 30454 0 0 seed=1257436991 Age maxvox sig=-3.74657 F=20.6006 at index 120417 0 0 seed=1257436991 mri_glmfit done
We haven't seen this before, and I didn't notice anything on the freesurfer wiki or email list about it.
The analysis I am working on is from the paired analysis section of the wiki.
I am using freesurfer version 4.5.
Here is my fsgd file: GroupDescriptorFile 1 Class Main Variables Gender Age Input 1038 Main 2 13.5808 Input 1039 Main 2 13.6986 Input 1040 Main 2 20.5616 Input 1041 Main 2 21.2575 and so on....(also, both males and females are represented equally)
Here are my contrasts: Mean 1 0 0 Age 0 0 1 Gender 0 1 0
and the mri_glmfit command:
mri_glmfit --glmdir sm15_output --y paired_diff_file.sm15 --C mean.mtx --C Gender.mtx --C Age.mtx --fsgd fsgd_file
Should I be concerned about this warning (i.e., am I setting up my analysis incorrectly)?
Thank you!
Best, Ryan