Dear Todd,
in SPM2, low-frequencies are in general delt with by discrete cosine
transformations (as regressors) with cycle lenghts up to a cut-off
frequency you choose (during the high-pass filtering option). Low
frequency aliases of physilogical rythms are dealt with properly that
way, as well as other low frequency confounds. They are simply not shown
in the design matrix, that's all. Guess that is similar in spm5 (we will
switch soon, but didn't do so yet, so I am not entirely sure about
that). See SPM.xX.K in SPM2 for details of these regressors, perhaps
someone else can point you to the SPM5 equivalent, when it exists. (in
fact, they are incorporated in the filter matrix applied to the design,
but that pretty much boils down to the same thing as including them, I
think).
Cheers,
Bas
Todd Penney wrote:
> Hi All,
>
> One quick question - I do not see any built-in options to include any
> functions that model effects of non-interest in SPM5 such as cardiac
> noise, resp noise, scanner drift, etc. Does this mean that the
> functions need to be built by the researcher and put in as regressors
> in SPM5?
>
> Thank you.
>
> Todd Penney
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Dr. S.F.W. Neggers
dept. of Psychonomics,Helmholtz Institute
Utrecht University
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