It is already built into the HRF model. If you need to shift them more or less than what is in the model, that can be accommodated. If you use the -spmhrf option, then you will get the same HRF as is used in spm.

Dear experts, 

I just have switched from SPM to Freesurfer. I am wondering if in FSFAST analysis, we require to shift the regressors in time to account for the delay in hemodynamic response?

Thanks

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