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Dear Chris, I got your files OK. Having looked at them, the problem is that your EPI image has very, very little anatomical tissue contrast in it. Since BBR relies on anatomical intensity differences in the EPI (even subtle ones) it cannot work well with such images. We have seen images like this before in multi-band data, and advocate the acquisition and use of a single-band image or one of the early unsaturated scans (i.e. the dummies that are normally thrown away) for use as a registration target, since these have good enough anatomical contrast for BBR to work with and it is straightforward to get a registration between these scans and the rest of the EPI images. If you don't have any other scans acquired then it will be difficult to get BBR to work. It might be possible to use something like the standard deviation of the motion-corrected timeseries to give you a surrogate image with more anatomical contrast, but otherwise I think you might need to stick with the non-BBR registration. All the best, Mark On 27 Mar 2013, at 17:13, Chris Keown <[log in to unmask]> wrote: > Thanks for the response, Mark. I uploaded some files to that link--or at least I think I did--so let me know if you don't see them. Any help would be much appreciated. > > Thanks! > chris