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Dear Professor Smith and Dr. Bartsch, Thanks a lot for the quick response. Would one of you mind dealing with one remaining doubt of mine? If I understand correctly without slice-timing correction FEAT will presume that all slices were taken after 2.5 seconds of each volume, when in fact each of the 37 slices were taken in the first 2 seconds. As slice-timing correction shifts "each time-series by an appropriate fraction of a TR relative to the middle of the TR period" I presume it will shift every time series by fractions of 5 seconds, which is not appropriate here. Is it necessary to input a slice timings file detailing the appropriate shift for each slice? I believe a value of 0.5 is no shift (and would thus represent 2.5 seconds in here). The slices were taken in interleaving sequence (0,2.....36, 1,3,.....35). Must I thus calculate each slice's timing by the following formulae? slice X timing for even slices = (((X/2)+1)/37)*(2/5) Where ((X/2)+1) will give each even slice its correct place in the order of acquisition from 1-37 (not sure if this should be 0-36 or 0.5 - 36.5 instead). I then divide by 37 in order to give each slice its time in terms of 1 TR, with 0.5 being no shift and representing 2.5 seconds in this case. I then multiply by (2/5) to correct for the fact that all slices were taken in the first 2 seconds of the 5 second TR Similarly the formula for odd slices would be ((((x+1)/2)+19)/37)*(2/5) where (((x+1)/2)+19) assigns each odd slice its correct place in the order of acquisition, and once again dividing by 37 normalises this placing to give timings in terms of 1 TR, and multiplying by (2/5) takes into account the fact that all slices were taken in 2, not 5 seconds. Otherwise tips on how to modify the model times would be equally appreciated. Many thanks in advance, Sean