Hi - it can be complicated in theory and in practice to mix up
analyses in this way. Were you feeding ICA spatial maps from multiple
subjects from each group into the cross-subject analysis? If you are
happy that you have identified corresponding components correctly then
you could probably most easily and informatively do this analysis via
randomise rather than FEAT, using the "fslmerge" tool to combine
multiple subjects' spatial maps into a 4D image before calling
randomise. Alternatively, maybe a simpler way to look for this group
difference is to use the tensor ICA option in MELODIC, feed in also
the cross-subject design matrix under the right-most tab, and the
report will then tell you which components statistically correlate (in
their cross-subject nature) with the two-group design.
Cheers, Steve.
On 22 Sep 2008, at 11:36, Eva Kenny wrote:
> Dear FSL,
>
> I carried out Melodic analysis separately on 2 subject groups, and I
> would
> like now to compare certain independent components between the 2
> subject
> groups. I tried to carry this out using FEAT higher-level analysis by
> inputting the component nii.gz files, but I got an error message
> saying
> registration had not been run, however I have carried out
> registration in
> Melodic previously. I tried registering the melodic component files
> again to
> standard space but the result does not look right.
>
> Any help would be greatly appreciated.
>
> Many thanks,
> Eva
>
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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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