I have a data set which comprises one group and the co-variate IQ. I would like to correlate this data set with the dependent measure LGI. I originally performed this in QDEC, however I read elsewhere that a vertex-by-vertex correlation cannot be done in QDEC.
Further, I read that it must be done via command line with mri_glmfit and the --pvr flag. I am confused as to what sort of file I should input into the --pvr flag (do I run a separate analysis?, etc).

Any advice would be extremely helpful.

Respectfully,

-Tim