Dear all,
I am obtaining fMRI data in .nii format from a philps 3T scanner. The technician reconstructs the data from the native format to nii before handing it to me. I am using afni_proc.py for analysis. The first thing that happens in data analysis is that 3dTcat converts the .nii files to .BRIK/.HEAD format. Now, 3dTshift takes resulting files (*.tcat*) as input and says that it is already aligned in time. One possibility is that the reconstruction process does slice-time correct the data. But the technician has no idea what the conversion software is doing so we don't know. Other possibility is that during the reconstruction process the timing info is messed up in the .nii file, which makes 3dTshift think that the tcat file is already slice-time corrected.

I looked through the previous thread on this issue:
[afni.nimh.nih.gov]
which was informative, thanks to Rick.

Since I am not dealing direcly with .nii files, my two questions are:
1. which fields in the *.tcat.HEAD file are supposed to reflect whether slice time correction has been done properly or not.
2. How important is it to do the slice-time correction in a block design? My design is - 15 seconds of stimulus, followed by 40 seconds of rest, repeated 6 times. I understand that it is critical for event-related designs.

I gather from previous threads that it will not be possible to tell whether a series is time corrected or not by just looking at the data.
Thanks a lot for your help,
Regards,
Gaurav