On 16 Sep 2008, at 20:40, Dost Ongur wrote:
> We are carrying out a VBM analysis but we have different numbers of
> subjects
> in the control and patient groups. The FSLVBM website indicates
> that you
> need the same number of subjects in each group to generate a reliable
> template.
> We have uneven numbers of subjects. We can't figure out a way to
> generate a
> template using the same number of subjects at the fslvbm_2_template
> stage,
You need to create a template_list file which contains a subset of
each of your groups. The maximum size of each subset will be limited
to the size of your smallest group. When fslvbm_2_template finds this
file it will create the template from only those files listed therein.
I have a perl script which generates the template_list file if
necessary. It also randomly picks the subjects from each group. If
you'd like I can send it to you off list.
> and then use the entire dataset at the fslvmb_3_proc stage. It
> seems that
> the generation of the template leads directly to the files used in
> the 3rd
> stage, and we are not sure how to add a few new subjects at that
> point.
What I do (and I'm not sure whether this is correct or not) is to
regenerate the template if I add more subjects to my groups.
Regards,
--
Dr Colm G. Connolly
School of Psychology and Institute of Neuroscience
The Lloyd Building
University of Dublin
Trinity College, Dublin 2, Éire
Fax: +353-1-671-3183
Please note that electronic mail to, from or within the Trinity
College Dublin, may be the
subject of a request under the Freedom of Information Act.
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