Dear Michael,
Both the present implementation and the dataset used in the tutorial are different from what was used in the 2008 paper (on which I was not a co-author). Since this is single subject data I wouldn't be worried too much. What you can do is look at the manual chapter showing how to create simulated MEG data with known ground truth and try to localise that. If you then find that something doesn't work as expected please let me know.
Also I remember that the forward model makes a difference for whether one gets a peak in the fusiform in that subject. It worked better with multiple spheres model.
Best,
Vladimir
On 19 Feb 2012, at 19:34, "Michael Spezio" <[log in to unmask]> wrote:
> Dear Vladimir,
>
> I'm using the tutorial data with Chapter 37 in the manual to try to replicate Friston et al.'s outcome (you are also a coauthor on that paper), and I'm not having any success. I've preprocessed the data in just the way the manual has indicated.
>
> What's very worrying is that the maximum intensity projection for both the Face and the Face - Scram mean ERPs that keeps turning up has maxima both at the occipital and anterior temporal regions, rather than at the expected fusiform location that the 2008 paper identifies and that is localized by fMRI. Without this confirmation on the tutorial data, I'm very concerned that using untested, new data will not result in interpretable results.
>
> Can you give me any insight into this issue? Is the way that Friston et al. implemented the MSP search different from the Greedy Search approach in SPM8? I haven't been able to locate anything in the archives on this issue.
>
> Using VB-ECD with 2-4 dipoles, I am able to find at least one dipole very near to the region identified by Friston et al, without specifying any informed priors. But I would like to use the MSP approach due in future, with untested datasets.
>
> Thank you for any help you can provide.
>
> Best,
>
> Michael
>
> Michael L. Spezio, Ph.D.
> Assistant Professor of Psychology
> Department of Psychology
> Scripps College
> Claremont, CA
> [log in to unmask]
> 909.607.0914
>
> and
>
> Visiting Associate Scientist
> Psychology & Neuroscience
> Division of Humanities & Social Sciences
> Caltech
> Pasadena, CA 91125
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>
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