Run the second level on the concatenated data OR on con_ images of the
mean of both runs after using 2 sessions in SPM instead of
concatenation. In either case, you will only have 1 observation per
subject in your model.
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
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On Mon, Feb 4, 2013 at 8:53 AM, Joao Pereira <[log in to unmask]> wrote:
> Dear all,
>
> I would like to ask your opinion on the best way for dealing with two runs
> per subject on the same BOLD experiment.
>
> I want perform a second level analyses on the data, and I've concatenated
> both runs in each subject and performed the statistics on the resulting
> (concatenated, one per subject) contrast maps. I was wondering, however, if
> there was another way of doing this or if this is the actually the best
> solution: could I perform a second level taking each run (two per subject)
> as an input (though this would create a statistical dependency in the
> model), or could I calculate the second level separately for each run and
> then mean both results?
>
> Thank you very much,
>
> Joćo
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