Dear Matthijs,
> We scanned 16 slices (diagonal from border v1 - cerebellum to mid
> frontal). When normalizing these functional images, SPM appears
> to either fill the entire brain space with this data, or turn the data
> horizontally.
> When we presented the data on the glass brain, a lot of activation
> was located outside the brain.
>
> Does anyone have a suggestion as how to solve our problem??
despite the fact, that the images are in the wrong orientation (rotate them
by pi in the yaw direction), you should take into account, that the
normalization procedure more or less assumes, that the image are oriented in
an axial view (world space). So you should rotate the images by -pi/4 in the
pitch direction.
If available, you should also coregister the images with an whole head EPI
(or anatomical) scan and normalize that. I guess, in your case, this will be
a more accurate solution, than normalizing only the rotated images.
I tried to normalize the rotated (yaw: pi, pitch -pi/4) images you sent, and
the result was more or less good. You should also play with the number of
basic functions or with only linear transformations, if no whole head image
is available.
Good luck,
Karsten
----------------------------------
Dipl. Phys. Karsten Specht
Medizin Center Bonn
Spessartstrasse 9
53119 Bonn
Germany
Phone: ++49-(0)228/90 81-178
Fax: ++49-(0)228/90 81-190
E-Mail: [log in to unmask]
WWW: http://www.mcbonn.de/Praxis/praxis15/fmri1.htm
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