Hi spm-ers,
I have a question regarding smoothing of functional data. I've read some
old mails and some of the course notes but haven't found a satisfactory
answer yet.
I have 20 slice volumes with 1.875x1.875mm voxels and 5mm thick slices. I
would like to smooth the data to facilitate analysis. Unfortunately, parts
of our analysis require this 20 slice model, so for the moment I am stuck
with non-isotropic voxels.
QUESTIONS:
What are the pitfalls of smoothing a ~1.9x1.9x5mm voxel using a 4mm kernel
(i.e. a kernel less than the z-dimension)? What about a 6mm kernel? Would
6mm be better than 4? Would 8 be better than 6?
Does SPM recognize the size of the voxels when smoothing?
Can you suggest any references?
thanks for any leads,
-jim
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Jim Eliassen, Ph.D.
Box 1953
Dept. of Neuroscience
Brown University
Providence, RI 02906
office 401-863-9984
lab 401-863-1874
fax 401-863-1074
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