Design Efficiency: Part 2 (SPM)

As an addendum to the previous post detailing looking at regressor correlations in AFNI, a similar procedure can be done in SPM. After specifying a first-level, an SPM.mat design matrix should be generated. Navigate to the directory containing the SPM.mat file, and type "load SPM.mat".

The contents of the SPM.mat file can then be listed by just typing SPM (all caps). Running the following command will produce a NxN matrix (with N = number of regressors):

corr(SPM.xX.X)



Matching up each column to each regressor can be found in the output of SPM.xX.name