It removes the user-specified "nuisance" regressors (eg movement
parameters) from estimation of the temporal autocorrelation
(nonsphericity). I think this was discussed in the emaillist by Torben
Lund a while ago (but which I admit I cannot find now, so am probably
misremembering). I haven't explored whether it actually makes much
difference in practice.
Rik
> Dear Dr. Henson, Dear SPM experts
>
> as I wrote yesterday, Volkmar Glauches answer on the mailing list
> resolved my problem that I had with your script.
>
> Nevertheless I have a last question regarding one section in your
> script that is not clear to me:
> What does the script in the "Update real/nuisance in design matrix
> (for nonsphericity corection)" section.
> Is this a usual step that is automatically included in SPM5 analyses
> when you do them without batching. Or is this a special feature that
> you added for yor purposes.
> In other words In a 'simple' first level event-related analyses with 6
> movement parameters/session, is this step necessary?
>
> Thank you very much for your help!
>
> Best regards
>
> Bernhard Haslinger
>
--
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DR RICHARD HENSON
MRC Cognition & Brain Sciences Unit
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Cambridge, CB2 7EF
England
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