Dear SPMers
I am doing my second fMRI study investigating memory. Therefore I am very
interested in localising activation changes in the medial temporal lobe. Now
I have 2 problems concerning normalisation:
1)I have normalised (using the default settings) the 3d anatomical images of
the 15 participants (all healthy male students) of the study and calculated
a mean image of the anatomy of my group. An overlay of this anatomical
group-mean with the MNI-Brain from the SPM canonical folder revealed
differences between the anatomy of my group and the MNI-brain, e.g. the
hippocampus of my group-mean-image lies some cm below the hippocampus of the
MNI-brain. I really have no idea why the normalisation does not match the
brains better. In my first fMRI study which I evaluated with SPM99 the group
mean of the normalised anatomical images of the participants matched the
MNI-brain quite good.
Now I am very insecure about the reliability of the localisation of my
activations. Which pictures should I use to overlay the contrasts? How
should I anatomically localise the foci of activation?
2) The normalisation of the anatomical images of 2 participants did not work
properly. I wonder, whether it would help to set the origin manually to the
AC?
Thanks a lot for any help!
Nadia
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Nadia Degonda, Dipl. Natw. ETH
Dept. for Psychiatry Research
University of Zurich
Lenggstr. 31
8029 Zurich
Phone: +41 1 384 26 89
mailto:[log in to unmask]
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