Using -regress_stim_types IM means the output will
have one beta for every single event. Is that what
you want? Because it is not explicitly mentioned,
I suspect it is not what you want.
Note that using -regress_stim_types AM does seem
appropriate, and it would not result in amplitude
modulation in this case, since there are no amplitude
modulators in the timing file. It would result in a
duration modulation regressor that is basically the
sum of all of the IM regressors.
If you want just one beta, AM seems the way to go.
- rick