Hello:

To my knowledge, there is no available routine to insert parametric modulators in the design matrix.
Since SPM-fNIRS utilities are to a large extent a repurposing of the SPM algorithms, it would seem that implementing parametric modulators should not be cumbersome.

Could you kindly provide a code snippet to implement parametric modulation or at least indicate what should I change in the code (in the function spm_fnirs_specify1st_ui.m) ?

Best wishes,

Mario