Hi Rodolphe,
> actually i work on a fmri children study. I tried to normalize my images both with the T1 template provided by SPM2 and whith th pediatric template called CCHMC .
> I was suprised to find many differences in cerebral activations between the two types of mormalization. if some images were barely the same, others were very different.
> The pediatric template seems to be less precise , maybe because of the big diffrences found in cortical anatomy of children with the same age.
> Can i conclude that its better to use the T1 template provided with SPM2??
My whole point of making the pediatric templates available was that,
yes, there are differences between a pediatric and an adult brain and
that consequently, differences in activation must be expected when using
different sets of reference data. The question is, which activation
pattern is closer to the "truth", whatever that may be. I believe that
the differences in anatomy between younger children and adults are so
profound that the results must be expected to be severely influenced if
adult data is used for processing. If you suspect that normalization was
less precise in the one or other case, you could check that by looking
at the resulting images, e.g. by creating an average.
Having said that, I of course still agree that the quality of the CCHMC
data is far from optimal. One way to improve normalization might be to
follow some kind of "optimized" processing in order to avoid the T1
entirely (this is also a good idea as non-brain tissue changes
substantially in childhood). In order to do this, you could segment your
anatomical data and normalize the gm-segment to the CCHMC gm map. If
your anatomical is in register with the functional, you can then apply
the parameters to the EPIs. This has worked rather nicely for my data.
Best,
Marko
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Marko Wilke (Dr.med./M.D.)
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Universitäts-Kinderklinik University Children's Hospital
Abt. III (Neuropädiatrie) Dept. III (Pediatric neurology)
Hoppe-Seyler-Str. 1, D - 72076 Tübingen
Tel.: (+49) 07071 29-83416 Fax: (+49) 07071 29-5473
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