> My analyse is this :
>
> single-subject whit 6 scans;
> condition (000111)
> covariate (111111)
> contrast (1,-1)
>
> I allege the matrix design and SPMresults;
>
> The grey regions, in the SPMresults , represent an contradiction of the
> null hypothesis ?
Six scans is rather a small number to get really statistically significant
results with. You may want to try using a few more scans.
The covariate of constant ones is not really needed, as the model already
contains a column of ones. (This column of ones is also not really needed
in this case, but SPM puts it in anyway.)
The grey regions are those voxels where the the likelihood of the null
hypothesis beeing true is lower than the threshold you specify. I would
suggest taking a look at Section 4.2 (page 27 onwards) of the following
http://www.fil.ion.ucl.ac.uk/spm/papers/SPM-Chapter.pdf
It includes an overview of how to make inferences about your results.
Best regards,
-John
--
Dr John Ashburner.
Functional Imaging Lab., 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
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