Hi Ziad & Rick,

Much thanks for the input. My intention in running volreg a second time was just to look at the plot of the distance from the original reference volume to the corrected volumes. I would just delete the data files produced. I think this is what Ziad was saying above about subtracting the reference volume? If the numbers in the plot are low and a visual inspection of the data looks good, is it safe to think that the corrections worked well? I've tried this out, and I get very small numbers for all subjects but one. It is clear from visual inspection also that corrections didn't work for this subject - he moved too much too fast.

Thanks, Rick, for the note about 1d_tool.py. I will definitely start using it. It appears that most of the subjects in question actually moved between runs -- especially if it was a sudden movement (some are more gradual). Would it still make sense to censor the time points? It was a long study, and I think they were getting antsy during the breaks between the last runs.

Christy