Dear Dr. Ashburrer:
Considering your comments, is there a problem with performing
high pass filtering prior to spatial normalization as our group has
recently been doing with several datasets?
Thanks alot
Jeff Lorberbaum
Medical University of South Carolina
On Mon, 23 Apr 2001, John Ashburner wrote:
> > Is it true that the pre-processing procedures such as alignment,
> > coregistration, smooth, slice timing, and normalization do not have
> > to follow some kind of order to apply to fMRI data before statistical
> > processing?
> > Logically, there may be some kind of order, but mathematically, these
> > procedures can be applied at any sequence order, and the results would
> > not be "too much" different.
>
> I thought I'd better just add a little more to Alle Meije's answer...
>
> I would strongly suggest that you follow the prescribed order of
> pre-processing as the steps are not commutative. e.g., warped images do not
> match together well with a rigid registration, smoothing before warping
> produces nonstationary smoothness etc...etc..
>
> Best regards,
> -John
>
>
> --
> Dr John Ashburner.
> Wellcome Department of Cognitive Neurology.
> 12 Queen Square, London WC1N 3BG, UK.
> tel: +44 (0)20 78337491 or +44 (0)20 78373611 x4381
> fax: +44 (0)20 78131420
> http://www.fil.ion.ucl.ac.uk/~john
> mail: [log in to unmask]
>
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