Dear Kris:
The issue of origins can be confusing. I would not suggest changing the
origins for the template. I am also surprised that you are able to normalize
the images with only 5 slices. Generally this doesn't work and it's better to
use the subject's own brain. But if you're set on normalization here's what
I'd do.
1) Since you're so high up in the brain your z origin should be 1. Hopefully
you also have an anatomical image on the person. You now have to figure out
which slice in your anatomical slice 1 corresponds to. You should have some
info on the coordinates of each slice. Once you figure out which is the
corresponding anatomical slice set the z origin for the anatomical to that
slice. I'm not sure what you're doing for the x and y origins but we generally
set them for the centers on both images. So if your functional is 64x64x5 and
your anatomical is 256x256x160 then your origins will be something like 32 32
1 and 128 128 100 (just an example).
2) Now normalize your anatomical image using the standard template in spm.
Then when you apply the normalization parameters to your functional image all
should be correct since the functional and anatomic images are in register.
Hope this helps,
Darren
Kris Boksman wrote:
> Hello again,
>
> We have still not been able to remedy our changing origin dilemma. If
> images are acquired at the motor cortex, so we're talking WAY WAY away
> above the AC, how do we analyse our results?
>
> I.E. Explicitly what is involved when changing the template origins? Can
> somebody tell us what steps to go through in what order. Please? We
> can't seem to get it by just fiddling.
>
> Thanks so much,
>
> Kristine
>
> ~~~~~~~~~~--
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Darren R. Gitelman, M.D. E-mail: [log in to unmask]
Cognitive Neurology and Voice: (312) 908-9023
the Alzheimer¹s Disease Center Fax: (312) 908-8789
http://www.brain.nwu.edu
Northwestern Univ., 320 E. Superior St., Searle 11-470, Chicago, IL 60611
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