Hi Katja,
A couple of things come to mind:
* The 4.67 hot spot doesn't intersect the average fiducial surface. Did
you map to the average fiducial surface, or use multi-fiducial mapping
(MFM)? The latter method is less vulnerable to this problem.
* There could be some very large "spiky" values throwing off the scale.
I can take a quick look and let you know what I think:
http://pulvinar.wustl.edu/cgi-bin/upload.cgi
Is the 4.67 hot spot in the left or right hem?
Donna
On 06/19/2007 05:05 AM, Katja Umla-Runge wrote:
Dear Caret users,
Mapping spmT*.img files (SPM99) to a surface in Caret, the resulting
image seems (at first glance) to fit the data table I obtained from
SPM. However, if I set the threshold to say t = 3,61 (metric -->
settings --> threshold --> Pos User = 3,61 --> threshold type: User)
which is the threshold I got from SPM for a given one-sample t-test,
less activations remain as compared to the SPM data table. As an
example, my results include an occipital activation with t = 4,67. If
I want to see this structure activated on my Caret surface, I need to
enter a threshold of about t = 1. Why do t-values and corresponding
activations do not correspond between the two systems? How can make
them correspond?
Thank you in advance.
Katja
--Dipl.Psych. Katja Umla-Runge
Saarland University
Department of Psychology phone: +49 - (0)681 - 302 4643
P.O.Box 151150 fax: +49 - (0)681 - 302 4049
D-66041 Saarbruecken email: [EMAIL PROTECTED]
www.BrainCog.de
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