Bump! If you know how melodic_IC is derived from melodic_oIC, please share!
I'm having trouble with a dataset where the z-values in melodic_IC are way too
high. Knowing what's supposed to happen would be very helpful to me in my
efforts to debug this.
On Wednesday, September 28, 2011 12:21:38 you wrote:
> It's been mentioned before that melodic_oIC contains the "raw" IC maps,
> that melodic_IC contains the Z-scaled IC maps, and that Noise_stddev_inv
> is used to convert the former to the latter. I'm curious as to precisely
> how this conversion is achieved. That is, given melodic_oIC, how do I get
> melodic_IC? The IEEE TMI paper seems to suggest it is a simple matter of
> doing voxel-wise division of each raw IC map by the standard deviation of
> the noise (technically the square root of the estimate of the noise
> variance), so:
> http://www.fmrib.ox.ac.uk/analysis/techrep/tr02cb1/tr02cb1/node8.html
>
> fslmaths melodic_oIC -mul Noise_stddev_inv my_melodic_IC
>
> But this doesn't seem to work. Indeed, lines 519-548 of meldata.cc would
> suggest something more is happening. Can anyone explain how to get
> melodic_IC from melodic_oIC using fslmaths?
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