Dear all,
I have a problem with activation clusters extending outside the brain.
I performed a second-level Rfx-analysis according to the instructions in the
SPM Help-facility and many helpful comments in the discussion list archives.
Things worked really well but the results were rather thin. After reading that
greater smoothing could enhance the results, I applied additional smoothing to
my first-level con*-files, as recommended in a correspondance in the archives.
Indeed, the results got better, i.e. the cluster sizes and significances
increased. Unfortunately, the clusters are now extending considerably outside
the brain.
My understanding was, that this should not happen after normalizing my images
to the same template before first-level analysis.
Now, how is this possible ?
What can I do to get rid of such "spurious" activated voxels outside the brain ?
Any comment would be greatly appreciated.
Thanks in advance,
Tobias
Tobias Flaisch
Dep. of Psychology
University of Konstanz
P.O Box D25
D-78457 Konstanz, Germany
Phone +49 (0)7531 884706
Fax: +49 (0)7531 882891
e-mail: [log in to unmask]
http://www.clinical-psychology.uni-konstanz.de/
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