Pengxu Wei wrote:
> I saw this problem in a space just above the top of the brain, e.g, the
> parietal lobe and frontal lobe. The MRI data was collected with 23
> slices per scan, and the upmost small part of the parietal lobe and
> frontal lobe was not contained.
This sounds a very bad idea to me, chopping off part of the brain for
a VBM study, but I have forwarded your question to the list to see
what others have to say on the matter.
> After SPM computation, some activeated
> areas appeared in the space which corresponded to the skipped, upmost
> small part of the parietal lobe and frontal lobe.
>
> I think the reason may be that, although some small part skipped during
> MRI scanning, that part will be 'filled' when normalization is done.
> And to complete the filling, nearby areas will meet distortion, that is
> the reason of my T-map problem.What is your opinion in terms of this issue?
I think it might be quite unpredictable what will happen when
normalising a brain with missing areas like this, but I think you
might be right that bits get distorted to fill the gaps. Possibly some
kind of cost-function masking (source image weighting) would help with
this -- see Brett http://dx.doi.org/10.1006/nimg.2001.0845
but you'd have to experiment a bit...
Best,
Ged.
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