Hi,

I think that you are right. I have to use a scatterplot instead of a correlation matrix. There are many ROIs and for each ROI I would like to calculate the correlation between AF and PLE. This correlation should reflect the mean over all subjects for each ROI (and not values for single subjects).

Each value/point/position in the scatterplot would represent the correlation between AF and PLE for different ROIs. In other words: the different ROIs are placed in the scatterplot depending on how high their correlation between the two measurements is.

ptaylor Wrote:
-------------------------------------------------------
> It is possible that if you have a lot of "derived"
> quantities in text files, not in volumetric
> datasets, you might be best off creating the
> correlation matrices (or scatterplots) in, say, a
> separate Python script.
>
> --pt

Exactly. I already used AFNI (3dTcorrelate) to calculate the AF-PLE correlation for different ROIs (via 3dROIstats) for each subject. So I have to use another program like Python or Matlab.

One more mini question though: When calculating the mean value (e.g. in a mask), it does not make a difference to use either 3dMaskave or 3dROIstats, right? By standard and if not specified by optional commands, both simply calculate the mean.