You should only put in one subject to each SPM.mat file for the first level analysis. Then use the con_images in the second level analysis. In regards to your error, the images are not normalized to common space and as such, SPM is complaining.

For each subject, you should do the following:
(a) slice-timing correction (optional)
(b) motion correction
(c) normalization
(d) smoothing

These 3 or 4 steps will lead to all subjects being in the same common space.

Best Regards, Donald McLaren
D.G. McLaren, Ph.D.
Postdoctoral Research Fellow, GRECC, Bedford VA
Research Fellow, Department of Neurology, Massachusetts General Hospital and Harvard Medical School
Office: (773) 406-2464
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On Fri, Mar 25, 2011 at 11:05 PM, Allison McMahon <[log in to unmask]> wrote:
Hello. I am trying to perform a group analysis on eight subjects using SPM8. I am using the Specify 1st Level option. Attached are some screenshots of the analysis. I have performed this same analysis on eight separate subjects and I receive an SPM.mat. However, with the current group of eight subjects, I am receiving the following error:

Failed: fMRI model specification

I am trying to perform this analysis in order to find the activated voxels for the group.

I would appreciate any help in resolving this issue.