We are currently working on this issue. It involves computing maps for
every combination of subjects.
On Thursday, May 5, 2011, Bob Spunt <[log in to unmask]> wrote:
> Hi, I searched the listserv and failed to find answers to this question.
> From what I understand, during second-level estimation (e.g., one-sample t-test) SPM performs the test only for voxels in which ALL subjects have data. In areas of the brain in which signal quality is highly variable from subject-to-subject (e.g., high susceptibility areas such as ventral frontal and temporal), this procedure is quite problematic, especially for large samples. Has any one customized the SPM algorithm to bypass the all-or-none exclusion procedure? I imagine this would require also producing a degrees-of-freedom image (e.g., to use when reporting statistics).
> Any tips would be much appreciated. Thanks in advance.
> Bob Spunt
> Doctoral Student
> Department of Psychology
> University of California, Los Angeles
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
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