[pymvpa] Is global intensity scaling a problem?

[Michael Waskom]

Hi Yarick et al.

In a typical FSL preprocessing pipeline, the timeseries images
are globally scaled such that the median of all four dimensions (within the
brain mask) is the same number across scans (usually 10000). To minimize
duplicated data, it would be nice to take the output of my preprocessing
and use it for both univariate and multivariate analyses, but I'm wondering
if this scaling step will introduce any bias. Is this a valid concern? And
does the answer change if I'm using a leave-one-run-out cross validation
approach?

Best,
Michael
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