help > RE: ROI-to-ROI Connectivity Line Color / Ball Mismatch?
May 4, 2021  09:05 AM | Alfonso Nieto-Castanon - Boston University
RE: ROI-to-ROI Connectivity Line Color / Ball Mismatch?
Hi Jeff,

Yes, exactly, the color of the connectivity lines represents the sign of the average connectivity across all subjects in the analysis (red for positive correlations, blue for anti-correlations), while the color of the spheres (at each target ROI center) represents the sign of the statistic that is being evaluated in this particular group-level analysis (e.g. if testing the correlation between connectivity and some covariate, balls colored red show positive correlations with that covariate and those colored blue show negative correlations with that covariate). The colors of the lines and balls will typically match if you are evaluating the average connectivity within a group (e.g. a one-sample t-test), while they will typically differ when evaluating other more complex contrasts.

Hope this helps

Originally posted by Jeff Browndyke:
I conducted a ROI-to-ROI regression analysis and noticed in the 2nd level model preview figure that there are some ROI connections that have a positive association with my regressed variable and understandably the ball marker for the associated ROI is red colored. However, in some cases the line connecting the ROIs in the positive association model in the preview figure are blue. What does it mean when the ball marker for the ROI is red, yet the connectivity line color is blue?

Does this mean that the ROIs in question are normally anti-correlated, yet the association between these ROIs and the regressed variable is positive (i.e., performance increases when there is increased connectivity in two ROIs that are normally anti-correlated)? Figure attached to illustrate the line color / ball color mismatch for some connections.

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Jeff Browndyke May 3, 2021
RE: ROI-to-ROI Connectivity Line Color / Ball Mismatch?
Alfonso Nieto-Castanon May 4, 2021
Jeff Browndyke May 4, 2021
Alfonso Nieto-Castanon May 5, 2021
Jeff Browndyke May 7, 2021
Alfonso Nieto-Castanon May 7, 2021