Hello,
> i have some questions about PPI...
>
> when the extracted time series, should i always adjust VOI region using the F-contrast(design matrix is composed of 3 condition) ?
It's always hard to say what you should "always" do. :) Generally
adjusting the VOI is a good idea, because it will remove activity that
can be explained by conditions you aren't interested in (e.g.,
movement, or in some cases, task-related activity).
> and i confused that "mean-corrects the time series"... What does this sentence mean exactly?
It means that the resulting timeseries is centered around 0 (more or
less). I.e. if you have a timeseries X, simply mean-correcting (or
de-meaning) would be: X = X - mean(X).
Hope this helps,
Jonathan
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