Reading through the fine SPM manual by Dick Veltman and Chloe Hutton I came across the following in the section on event related fMRI model specification" basis functions (Finite Impulse Response): uses a set of 'mini-boxcars' to model peri-stimulus time. In my version of spm99, this option is not available. If I search through the code of spm_get_bf, I don't see this. It also doesn't seem to be in the updates. This is a great way to do the analysis. I've been doing it by hand and it's a pain. Any info would be greatly appreciated. Thanks, Souheil -- Souheil Inati, PhD Research Assistant Professor Center for Cognitive Neuroscience Dartmouth College 6162 Moore Hall Hanover, NH 03755-3570 web: http://www.dartmouth.edu/~inati email: [log in to unmask] phone: (603) 646-0173 FAX: (603) 646-1181