Hi,
> I have recently started working with SPM by doing Voxel-Based Morphometry
> analysis. I'm only obtaining overcomes with uncorrected p, maybe because of
> my little N. I've tried to analyze a ROI with the eigenvariate function
> (according to chapter 31 of the "SPM8 Manual") but I haven't obtained
> anything. How can I proceed? I've also found the MarsBar toolbox, do you
> know if it is possible to use it for structural analysis?
In principle, using a region of interest is allowed if (a big if,
actually :) you have a prior hypothesis as to where you expect results.
These ROIs can then be derived from a number of sources (AAL, MarsBar,
the anatomy toolbox, etc.; caution may be necessary if you have used
your own template as then standard ROIs may not match your group).
Another approach may be to use DARTEL to process your data, potentially
increasing overlap. However, in most cases where people fear their
groups are too small, they actually are, and the only remedy is to add
subjects.
Hope this helps,
Marko
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Marko Wilke (Dr.med./M.D.)
[log in to unmask]
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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