Back to PLS HelpSampling to BOLD variability
Posted on 12/02/08 08:36:46
Number of posts: 60
Hello,
As it is sufficiently clear from PLS,the bold response is estimated as the deviation from t=0 (reference scan) for a given events during E.R.fMRI. There is also a Relative Ref. Scan Onset option which refers the offset of the first reference scan from the first scan of each onset. this means that you can specify a reference scan prior to the event-onset.But what if we set the refrence to the fraction of a scan(e.g. 0.77).If the ref scan can not deal with non-integer numbers then how can it deal eith sampling-to-BOLD variability?
Thanks
As it is sufficiently clear from PLS,the bold response is estimated as the deviation from t=0 (reference scan) for a given events during E.R.fMRI. There is also a Relative Ref. Scan Onset option which refers the offset of the first reference scan from the first scan of each onset. this means that you can specify a reference scan prior to the event-onset.But what if we set the refrence to the fraction of a scan(e.g. 0.77).If the ref scan can not deal with non-integer numbers then how can it deal eith sampling-to-BOLD variability?
Thanks
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Posted on 12/02/08 10:40:10
Number of posts: 291
I think it would be better to let you know how the "reference scan" works in PLS:
Each scan in PLS represents a volume of brain data. By choosing a "reference scan", we normalized the other scans by dividing the values of the "reference scan" to get a percentage change.
Therefore, "reference scan" is basically an index number to all the scanned images in one run, which must be an integer.
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