| My experience with activation maps is not that big, but I am familiar with some
| of the preprocessing items. And one thing the normalisation does, is to equalise
| the global mean of the normalised image to that of the template. So it might be
| possibble that:
| - the values the activated areas decrease a little (change in intensity)
| - as a result, less of the activated areas is higher than the threshold, so less
| is coloured.
Actually, the scaling so that the globals are about the same doesn't do anything
to images that are written out during the spatial normalisation process. It
merely makes the warping a bit more stable. i.e., if the intensity scaling is
orders of magnitude different between the template and source image, then lots of
problems can occur due to having very badly conditioned matrices. Once the warps
are estimated, the values used to rescale the images are not used anywhere else.
|
| > 2. I found the individual render image can provide the fashion of SPM99,
| > i.e. 6 views. I need the display of SPM96 fashion, i.e. 8 views,
| > including
| > the medial aspects of the brain to see the cingulate and thalamus .......
| > Is there anyone has a way to do display of individual render images with
| > 8
| > views? (maybe the default is SPM99 fashion, but some how we can define it
| > to
| > do SPM96 fashion, just as the option provided by standard SPM99 for
| > normalized data........)
I'm afraid there is quite a lot of messing about to do medial views as there
are no routines in SPM99 that can easily separate the left and right hemispheres.
All I can suggest is that you use the "render_spm96.mat" file for rendering
the images. If you want to render medial views of single subjects, then I'm
afraid that you have to laboriously edit the *_seg1.img and *_seg2.img files so
that they just contain half a brain (making sure that any .mat file info,
scalefactors etc are retained). There are a few packages out there that you can
use to do this. Can I suggest you try Chris Rorden's MRIcro package:
http://www.psychology.nottingham.ac.uk/staff/cr1/mricro.html
Best regards,
-John
|