Hello,
Just to second everything Marko said, and also clarify that you can
certainly use MarsBar for structural analysis; most likely you'll have
one gray-matter image per subject, and MarsBar will then give you a
value per subject (e.g., average over all GM voxels within an ROI).
Good luck!
Jonathan
On Wed, Mar 3, 2010 at 10:53 AM, Marko Wilke
<[log in to unmask]> wrote:
> 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
> --
> =====================================================================
> 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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