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Hi Colin, Thanks for your feedback, and for checking that out with your data! I'm guessing the default with the FSL function --fd is also 0.5mm: http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/FSLMotionOutliers J. ps. Very cool concept with Neuroanalysis Consulting, and the idea of outsourcing analysis! And I see you work with Jean here at Rotman! On Thu, Feb 4, 2016 at 10:47 AM, Colin Hawco <[log in to unmask]> wrote: > I think 0.5mm is reasonable if you are using framewise displacement (i.e. > the difference in motion parameters for successive TRs). > > > > I did a quick check on some data I have on hand, and there was relatively > few TRs at 0.5mm. The ones which were >0.5mm seems to be pretty clear > motion spikes, and I suspect at a lower threshold (e.g. 0.3mm) you will end > up reinterpolating a lot of data points. . > > > > If you have not read it I recommend Johnathan Power’s paper > http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3849338/ > > > > They define 0.5 as lenient and 0.2 as stringent, and I think the effect of > using either (or an intermediate) threshold depends a lot on the character > of your data. > > > > I also think it is not unreasonable to try a few threshold and see how > many TRs are censored, and use that as a guide, For example, if 05 removes > 2% or TRs and 0.3 removes 5%, maybe 0.3 is a good choice (removing motion > more aggressively but not destroying data integrity). Just in that case > report that you did this. > > > > Good luck! > > > > Colin Hawco, PhD > > Neuranalysis Consulting > > Neuroimaging analysis and consultation > > www.neuranalysis.com > > [log in to unmask] > > > > > > > > > > *From:* FSL - FMRIB's Software Library [mailto:[log in to unmask]] *On > Behalf Of *Joelle Zimmermann > *Sent:* February-04-16 9:47 AM > *To:* [log in to unmask] > *Subject:* [FSL] framewise displacement > > > > Hi FSLers, > > I was wondering whether 0.5mm was a reasonable value for frame-wise > displacement cutoff for removal of motion outliers using interpolation? > > Thanks, > > Joelle >