Gaël wrote:
>Hi,
>My question concerns fMRI model specification: in our event-related fMRI
>experiment, first trials (or events) occured before scanning onset (the
>first scan started as the 6th trial occured). Since the stimulus onset
>asynchrony was short (mean=6s), the brain activity level at the first scan
>should have been influenced by these "pre-scan" trials. Could this
>condition interfere with model estimation? Is it possible to specify these
>pre-scan trials (corresponding to negative onset scan numbers) in the model?
>Many thanks,
>Gaël.
>
>
Yep, with SPM2 negative onset times is possible
Torben Lund
Danish Research Centre for MR
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