Hello,
> When you include motion regressors in your design
> matrix, are these columns of the design matrix automatically included in
> the final activation map without explicitly including them in a
> contrast? In other words, is motion already corrected for when looking
> at a final SPM (as in the first attachment spm.jpg) or do you include -1
> -1 -1 -1 -1 -1 in your contrast (as in the second attachment
> spm_motion.jpg) to include the motion regressors in the final
> statistical parametric map?
I would guess that you hope the answers are "yes" and "no", and they are
:) The idea behind including the motion regressors in your design is
that you want to model the variance they might explain in your data as
this variance may be due to motion. If you include the regressors (as
you did) then the variance attributed to them will only be seen if you
do an f-test (as you want to see both positive and negative activation)
along the lines of 0 0 1 1 1 1 1 1 ; if you do 1 -1 you will only see
the effect of the first two regressors.
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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