Hi Doug,

I asked you about how to perform group analysis on maps created using an index I calculated. You suggested using mri_concat to concatenate the maps and then perform the analysis using mri_glmfit.

I then asked about NaN values in the maps and how freesurfer treat these values. You said "It will probably crash. I does nothing to find NaNs and handle them in an appropraite way"

When concatenating maps with NaN values, the following lines are printed out in the terminal:

WARNING: #number NaNs found in subjid.map.mgh

but it creates the concatenated mgh file. However, if maps from all subjects contain NaN values, it does not create the corresponding mgh file. My question is: Does it mean that it discards subjects with NaN values??

Ladan