Hi Dost,
If you're putting a seed voxel's timecourse back in as a regressor of
the same data, you should definitely see that voxel (and probably
neighbouring ones) as highly 'activated' - so it does sound like
there's a problem here. Is it possible that you forgot to turn off the
HRF convolution for the final FEAT run? The voxel-extracted timecourse
already contains the HRF convolution.
Cheers.
On 1 Feb 2008, at 19:44, Dost Ongur wrote:
> We have recently started to perform whole brain signal correlations,
> to test
> hypotheses about resting state circuits based on our ICA. Our first
> such
> test used the LMFG portion of area 46 as the seed ROI, and we
> noticed that
> neither patients nor controls yielded significantly correlated
> voxels in
> left sided area 46 itself. Does FEAT know to exclude the seed ROI
> in some
> fashion, or are we simply looking at poor auto-correlation within
> the ROI?
>
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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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