dear spmers.
i searched the archives about a question about motion correction and
covariate for the model, but did not find a sufficient answer (some were to
technical for me to understand, sorry about that).
i always understood realignement in spm in the way, that afterwards (after
reslicing the images) spm corrected for the motion between the images. for
me it sounds like after that, almost no differences in motion between the
images exists, the images almost "look" like one static image over the
whole time series. (maybe here i am wrong, please correct me).
now i read in many mails, that it is recommended to integrate the
translation and rotation data of the rp-file as a covariate into the model
to control for movement effects.
now my question:
if both of my above assumptions are correct, why should i integrate the
motion covariate? didn't i control for movement artefacts by the
realignement procedure itself? i thought that the rp-file gives me
information about the rotation and translation which results in the new
images after realignement. integrating those also in the model would be one
step to much?
if i still have to integrate the regressor, did i understand it right to do
it in the first-level procedure?
thanks in advance
markus burgmer
university münster, germany
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