Hi!

To evaluate reproducibility, I compared two set of ICAs. I found information about how the Dice similarity coefficient (DSC) is calculated online, so I have an idea how that works, but there is another option in conn, calculation of the 'correlation' which yields an r value. But I found no information about how this is calculated in the manuals.
Is it e.g. calculated form thresholded whole-brain voxel z-scores of the functional maps? Can I read about this in some kind of documentation?

Thanks in advance

Originally posted by doora:

Hi all,

I am also interested in finding out how the spatial correlation coefficients are calculated and what do they mean. Could somebody provide guidance?

Thanks,
Tsvet

I found a paper by Grecius et. al. (2004) "Default-mode network activity distinguishes Alzheimer's disease from healthy aging: Evidence from functional MRI", which seems to provide an explanation of spatial correlation:

"Next, a template of the default-mode network was used to select the "best-fit" of the remaining low-frequency components in each subject. To do this, we developed a nonlinear template-matching procedure that involved taking the average z score of voxels falling within the template minus the average z score of voxels outside the template and selecting the component in which this difference (the goodness of fit) was the greatest. z scores here reflect the degree to which a given voxel's time series correlates with the time series corresponding to the specific ICA component."

The paper has been cited close to 3500 times so I suppose it serves as a guide in the lierature. Is this the approach adopted by CONN? I have searched in the forum and could only find this question from last year, which was unaswered.

Originally posted by Tsvetoslav Ivanov: Hello,
Do you have any idea what is the exact criteria (e.g. a value of correlation coefficient) that CONN use to draw the red squares (the size of the red square)?
Thank you!

hi,
I wonder if you got the answer?
Thank you!

Hi everyone, 

has anyone received this information? 

Thanks