Dear SPM experts,
I would like to enter the reaction time as a parametric modulator, but I don't want to modulate the amplitude, but rather the length of the HRF response, as described by Grinband et al. (2008) , see http://dx.doi.org/10.1016/j.neuroimage.2008.07.065
I gave a search and found this http://wagerlab.colorado.edu/wiki/doku.php/help/fmri_help/fmri_statistical_models/parametric_modulation , but it seems some additional scripts are needed. Is anyone familiar with this topic and could provide some more information?
Thank you,
Helmut
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