Hello AFNI developers & users,

I want to use AFNI to analyze fMRI data acquired with interleaved silent steady-state (ISSS) sequence. The trial length was 10 s, including 2 dummy scans and 3 real scans with a TR of 2 s. Auditory stimuli, which were 0.5 s in duration, were always presented within the first dummy scan. I have 720 volumes in total in response to 240 trials of stimuli (3 volumes for 1 trial).

I have tried to average each 3 volumes by 3dMean, re-concatenate the 240 new volumes by 3dTcat and define the TR at 10 s, and run 3dDeconvolve like a sparse sampling design. However, this way did not give good estimates for my study. In particular, it lost the precise timing information and can not accurately model the HRF.

Does anyone know how to play with ISSS data without volume averaging and keep the timing information?

Many thanks,

Yi