Dear all,
As stated in the FSL support material, in a recent manuscript I cited fully FSL and stated that "grand-mean intensity normalisation of the entire 4D dataset by a single multiplicative factor" was carried out.
I didn't think much of this at the time - I understand grand-mean scaling to account for slow-frequency signal changes related to scanner drifts - but one of the reviewers rightly questioned how a single value can be used to normalise ALL the volumes within a time-series.
I have been unable to find any related posts about this, so I suspect that I'm overlooking something fairly simple. But if someone could show me exactly what I'm missing I'd be very grateful.
Many thanks in advance,
Dan.
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