I could be mistaken, and I don't have time to parse the code again right now, but I think that's there to allow small, negative onset times.
I think the code that contains references to that might include spm_fMRI_design, spm_fmri_spm_ui, spm_get_ons, spm_dcm_create, spm_dcm_specify, spm_dcm_U, spm_hdm_ui, spm_peb_ppi, though that list might be out of date; you can look on a Linux/UNIX box by going to the SPM directory and typing
grep 33 *.m
and then wading through the results.
Some listserv posts/threads that might be related include:
* https://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=SPM;b5a2dd09.03 ("You can now also specify negative onset times up to 32 time bins (that default to 1/16 inter-scan intervals).")
* https://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=SPM;4da16ab5.0908
|