Hi,
sorry to be a bit late:
> When I use MRIcro to visualize both positive and negative SPM maps, I
> need to specify a t threshold, which corresponds to a P value when I use SPM
> to visualize the results.
If you load a structural in MRIcro and then choose a spmT_xx.img as an
overlay, you should specify the cutoff as found by spm. If you look at
your results in spm, this cutoff (which of course depends on your
method, like FWE or FDR etc.) will be shown below the glass brain. It
may be in the range of t = 3.xx or so. To look at both positive and
negative correlations, you could load two t-maps according to the 2
contrasts specified in spm.
> Should I report the threshold as 2*P if I show
> both the positive and negative values since it is now a two-tail test? If
> I'm not wrong, SPM only calculates one tail P value.
I don't think this has anything to do with the displaying issue.
Best,
Marko
--
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Marko Wilke (Dr.med./M.D.)
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Universitäts-Kinderklinik University Children's Hospital
Abt. III (Neuropädiatrie) Dept. III (Pediatric neurology)
Hoppe-Seyler-Str. 1, D - 72076 Tübingen
Tel.: (+49) 07071 29-83416 Fax: (+49) 07071 29-5473
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