Dear Ruth,
At 22:54 10/07/2000 -0400, [log in to unmask] wrote:
| According to the SPM HELP files, it should be possible to access
| the SPM96 format for setting up the design matrix.
| However I can't find the SPM96 options on the menu for
| PET/SPECT analysis. Can you please tell me how to implement an
| SPM96 analysis for PET under SPM99?
The SPM96 PET/SPECT models *are* available in SPM99, but are hidden. To
access them, start SPM99 and type:
spm_spm_ui('cfg',spm_spm_ui('DesDefs_PET96'))
in the MatLab command window.
There are a number of differences between the options offered in the SPM96
and SPM99 PET/SPECT models. Basically, the SPM99 PET/SPECT models have been
pre-configured to be subject separable, such that all effects by default
are fitted in a subject specific manner. Also, centering of covariates is
by default done in a subject specific manner, as is grand mean scaling (the
subjects grand means are scaled individually).
In almost all the PET/SPECT data sets I've looked at there is evidence of
such subject specific effects.
-andrew
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