Thanks for the response! I think stim_times_IM is what I wanted. However, when I tried this command, I got the error:
FATAL ERROR: 3dDeconvolve dies: Insufficient data (2151) for estimating 2400 parameters
I think this error occurs because the duration of the regression function I'm using is longer than some of the trials. I tried using the '-allzero_OK' option as indicated in '3dDeconvolve -help', but it didn't help. The '3dDeconvolve -help' also says: "Probably you should fix the times in the 'tname' file instead of using '-allzero_OK'". How should I fix the times?
Thanks!