Hi,
On 21 Oct 2007, at 22:45, Marc Dubin wrote:
> It seems that according to figure 7 in Smith, et al (2006) in
> NeuroImage that the selection of an internal target does not affect
> the results significantly. Am I correct to assume that?
Not quite, this is showing that if you choose the best (most typical)
target from different groups it barely changes things. You wouldn't
want to just pick one subject at random as they could be quite an
outlier.
> Then N*20min becomes much faster. Another option would be to take a
> random sample of the N (say 25%) and then pick the best
> target...then it would be ( 0.25)*N*N*20min.
I suppose you mean 0.25*0.25*N*N*20min. Yes, this should be ok if
your N is high.
Cheers.
>
> On 10/21/07, Steve Smith <[log in to unmask]> wrote: Yes -
> because it is much higher resolution than a native single input
> image. However, if you only do N*5hrs that is quicker than N*N*20mins
> once you have a sensible number of subjects.
> Cheers.
>
>
> On 21 Oct 2007, at 19:55, Marc Dubin wrote:
>
> > Hello FSL users,
> >
> > Does anyone understand why tbss_2_reg takes much longer to run
> > (5hours) if the FMRIB58 target is
> > used compared to using one of the subjects as the target with the -
> > s option (20 minutes per
> > registration?)
> >
> > Best,
> > Marc
>
>
> ----------------------------------------------------------------------
> --
> ---
> 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
> ----------------------------------------------------------------------
> --
> ---
>
>
>
> --
> Marc Dubin, MD PhD
> Resident in Psychiatry - PGY4
> Weill Cornell Medical College
>
> 212-746-3764 (w) 646-831-8886 (c)
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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
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