[pymvpa] question about detrend and zscore

[Yaroslav Halchenko]

On Tue, 06 Oct 2009, John Clithero wrote:
> The 'wb_file' is func data with the relevant timepoints... it has had
> some preprocessing done in FSL (motion correction, slice timing, brain
> extraction). The ROI mask is a whole brain mask. It seems (I hope)
> that the NiftiDataset is being put together correctly.
wild guess - may be while doing FSL preprocessing you've done some
intensity normalization?


> This perfect negative correlation occurs even if I feed in arbitrary
> labels to the NiftiDataset, so there must be some sort of error in how
> I'm using detrend and/or score?? I am guessing this is my erros since
> the raw feature data looks fine to me.

> This perfect negative correlation also occurs after just implementing
> "zscore" or "detrend", although obviously the values are different.
so, they aren't present in just loaded dataset but if you do zscore or
detrend -- they come?

could you just plot 1 voxel (which later carries perfect correlation)
before/after detrend?

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