Hi - in fact there is no need to orthogonalise your main EVs wrt the
motion regressors - inference on the main EVs is only driven by the
orthogonal component anyway so you don't need to do anything.
Cheers.
On 18 Jun 2007, at 13:44, Amanda Bischoff-Grethe wrote:
> Hello,
>
> We have a design with several task related EVs for which we have
> turned on the temporal derivative option. Because our motion
> correction was handled outside of FEAT, we have chosen to
> explicitly describe them in the model as additional EVs (rather
> than use the motion regression checkbox). We plan to set our task
> related EVs to be orthogonal to the motion regressor EVs. Does the
> orthogonality option only apply to the original EVs, or does it
> also apply to the temporal derivatives of our task EVs as well? If
> the temporal derivatives are not orthogonalized to the motion EVs,
> is there a way to do so?
>
> Thanks,
> Amanda
>
> --
> Amanda Bischoff-Grethe, PhD
> Assistant Project Scientist
> Laboratory of Cognitive Imaging
> VA San Diego Healthcare System
> 3350 La Jolla Village Drive, M/C 151B
> San Diego, CA 92161
>
> Phone: 858-552-8585 x2480
> Fax: 858-642-1458
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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)
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