afni.nimh.nih.gov

Hi, the -peak option refers to the peak of the function you use (GAM, in this case). When you have events close in time (such as during a blocked design), the various gammas add up to more than 1. If you try having a .1D file with just a single "1", and run the same command, you'll see that the resulting gamma has a peak = 1 (of course, the 2 s resampling will make it such that you may not see the exact peak in the actual output).