Hi, It is still very helpful to use BBR without fieldmaps. In my experience this gives a substantially better registration, and is good in all parts of the brain except where there is distortion. However, the 6 DOF option is prone to global inaccuracy - especially shifts along the superior-inferior axis. So I strongly recommend using BBR. All the best, Mark On 28 Jan 2014, at 15:23, Andreas Werner <[log in to unmask]<mailto:[log in to unmask]>> wrote: Dear FSL List, when fieldmaps are not available for deformation correction, is there an expert consensus how to register T2* funtionals to native T1 volumes ? Specifically: is it enough to use 6 degrees of freedom in this case ? Is it still sensible to use "BBR" in FEAT Gui ? Cheers, Andreas