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Hi, On 19 Mar 2006, at 21:57, Lu Yuefeng wrote: > Hi Steve, > > Thanks a lot for your advice! I got two questions > > (1) I was wondering when I analyze the simulated brain, whether I > could turn off some options to prevent using spatial information > to estimate noise/covariance. Indeed, that's right. > (2) If you would clarify the following question, that would be very > helpful for my understanding of SUSAN algorithm. When the same time > series were put into a big enough clsuter, would the noise variance/ > covariance estimates for the time series on the center voxel be the > same as those estimates from a single time series, when SUSAN > algorithm is used? If you set the mean intensity of the voxel of interest such that it's very different from the mean of its neighbouring voxels, then SUSAN will not include those voxels in the whitening estimation. Good luck - cheers, Steve. > > TIA! > > Yuefeng > > > > On 3/18/06, Steve Smith <[log in to unmask]> wrote: Hi - probably > the easiest thing is just to generate a fake dataset > using this timeseries - eg use the matlab tools to generate a 4D > dataset with say a few centre voxels containing the same timeseries > (plus a nonzero mean) and then a few empty voxels round the outside, > then use save_avw to save to nifti file. > > Cheers, Steve. > > > > On 18 Mar 2006, at 05:00, Lu Yuefeng wrote: > > > Ladies & Gents, > > > > I am sorry if the following question has been asked before. I > > simply can't find from the achives of this mailist. > > > > I know how to and have used "feat" to estimate the HRF's over a > > whole brain. I am wondering whether FSL can do the deconvolution > > for single time series when stimuli are given, and how. > > > > It looks to me "feat" might not be able to do this, since it have > > used the "susan" algorithm, which uses local voxels, to estimate > > noise covariance. I guess flim_gls may be the right tool but I > > couldn't find enough help information on how to use this. > > > > Any information would be highly appreciated! > > > > Yuefeng > > > ---------------------------------------------------------------------- > -- > --- > Stephen M. Smith, Professor of Biomedical Engineering > Associate Director, Oxford University FMRIB Centre > > FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK > +44 (0) 1865 222726 (fax 222717) > [log in to unmask] http://www.fmrib.ox.ac.uk/~steve > ---------------------------------------------------------------------- > -- > --- > ------------------------------------------------------------------------ --- Stephen M. Smith, Professor of Biomedical Engineering Associate Director, Oxford University FMRIB Centre FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK +44 (0) 1865 222726 (fax 222717) [log in to unmask] http://www.fmrib.ox.ac.uk/~steve ------------------------------------------------------------------------ ---