Dear SPMers,
I think the previous question that I asked was somehow related to this question.
I would like to explain my question a bit more here.
When I got a result from the mirror brain, all clusters that meet the
requirements during the estimation of model process show up. How can I only
display a certain number of clusters which I can specific the x,y,z coordinates
by myself using SPM99?
Thanks,
Anson
Quoting Jared Van Snellenberg <[log in to unmask]>:
> Dear SPMers,
>
> I apologize for repeating a question that has been asked twice now in the
> list
> before, but I haven't seen an answer that is clear to me.
>
> I'm writing some custom analysis scripts and I'm wondering how it is that
> clusters are defined in SPM. Specifically, what is the requirement for a
> voxel
> to be considered to be part of a cluster. It seems from looking at
> spm_clusters.m and spm_bwlabel.m (I don't know C and so can't make sense of
> spm_bwlabel.c) that they can be defined as 6(surface), 18(edge), or
> 26(corner)
> and that SPM uses 18(edge) by default. The problem is that I'm not sure I
> know
> what this means.
>
> Is it that surface means adjacent voxels must have two (of 3) coordinates in
> common and be adjacent on the third dimension, edge means adjacent voxels
> must
> have one coordinate in common and be adjacent on the other two, and corner
> means that they need have no voxels in common but must be adjacent on all
> dimensions?
>
>
> Thanks in advance for any help,
>
> Jared Van Snellenberg
> Laboratory for Affective & Developmental Neuroscience (www.sfu.ca/ladn)
> Department of Psychology, Simon Fraser University
> RCB 4209, 8888 University Drive,
> Burnaby BC, Canada V5A 1S6
> Phone: 604-291-3013
> Fax: 604-291-3427
>
--
Anson C. M. Chau
Instructor in Radiography
Oral Diagnosis
Faculty of Dentistry
The University of Hong Kong
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