shanusmagnus,

Thank you kindly for your reply! I will give the BLOCK function a try. However, a more general question, does AFNI need the duration information? If I use a regular "GAM" -- will AFNI be able to infer how long my stimulus is, or will it assume that it is the length of the TR? Or, will it not matter? I looked at the x-matrix and it appeared that the GAM and BLOCK stim durations appear to be identical (ie., in width).

One last question (I hope!): In the past, I've been able to use stim times (in AFNI) with a colon that indicates on and off times, for example, 3.5:7 for a stimulus that starts at 3.5 seconds and ends at 7 seconds. I'm having difficulty do that now... is this still possible? I know there isn't a standard formalism for any of this, but what is the recommended function for dealing with basic event-related experiments? Is it GAM, or would you still suggest the BLOCK function with BLOCK(3,1)?

Thank you very much again!

Cheers,
cephalopod