Hi David,
I'm surprised that this gives a TR of 2.5099999905 in the GUI - when I load in a file with a TR of 2.5125000477 locally, that is the value that appears in the TR box. Either way these are fields that are set from the scanner information when the NIFTI file is first created- so I suspect that the exact scanning TR was not exactly 2.5s. You can manually set the TR to 2.5 in the GUI after loading the 4D data, however it would be best to check with the scanner operator what the actual scanning parameters were.
Kind Regards
Matthew
sure the output of fslinfo is
data_type INT16
dim1 64
dim2 64
dim3 29
dim4 287
datatype 4
pixdim1 3.2031250000
pixdim2 3.2031250000
pixdim3 3.1999664307
pixdim4 2.5125000477
cal_max 0.0000
cal_min 0.0000
file_type NIFTI-1+
Cheers