Michael W. ColeSep 21, 2023
Lab’s latest: “Regularized partial correlation provides reliable functional connectivity estimates while correcting for widespread confounding”, wherein we demonstrate a major improvement to the standard fMRI functional connectivity measure (correlation) https://doi.org/10.1101/2023.09.16.558065
A thread... 1/n
Show threadMichael W. ColeSep 21, 2023
In brief: Improvements to pairwise (standard) correlation: 1) reduced false connections (confounding), 2) reduced sensitivity to in-scanner motion, 3) better correspondence to task-related activity, and 4) more interpretable links with individual differences in behavior 2/n
Show threadMichael W. ColeSep 21, 2023
Pairwise correlations are known to be susceptible to false positives in theory. For example, region A causing activity in unconnected regions B and C (B<-A->C) can lead to a false B-C connection. Partial correlation can correct for this error, but not reliably 3/n
Show threadMichael W. ColeSep 21, 2023
We hypothesized that low reliability of partial correlation is due to overfitting to noise, with regularization (model simplification) improving reliability. 4/n
Show threadMichael W. ColeSep 21, 2023
In simulations, pairwise (standard) correlation led to many false connections, but so did partial correlation. Regularized partial correlation (glasso) better recovered the true network organization 5/n
Show threadMichael W. ColeSep 21, 2023
This pattern of results was mirrored in empirical resting-state fMRI data across 4 validation measures. Regularization was key to estimating individual subject-level networks with reduced confounding. 6/n
Show threadMichael W. ColeSep 21, 2023
First empirical validation: regularized partial correlation was much closer to structural connectivity, which doesn’t have the causal confounding problem (despite other issues) 7/n
Show threadMichael W. ColeSep 21, 2023
As another empirical validation, regularized partial correlation was much less susceptible to motion artifacts than pairwise correlation. Percent connections linked to motion = Pairwise correlation FC: 51.1% vs. graphical lasso FC: 0.03% 8/n
Show threadMichael W. Cole
Also empirical, prediction of task-evoked activity (via activity flow modeling) was better with regularized partial correlation 9/n
Sep 21, 2023 at 6:17pmWeb
Show threadMichael W. ColeSep 21, 2023
And regularization improved prediction of individual differences in demographics (age) and behavior/cognition (general intelligence) relative to standard partial correlation. The glasso results were more interpretable than pairwise correlation (fewer false connections) 10/n
Show threadMichael W. ColeSep 21, 2023
Together, results demonstrated a vast improvement in functional connectivity estimation using regularized partial correlation (glasso), and we suggest replacing pairwise correlation with regularized partial correlation as the new field standard. Thanks to the first author Kirsten Peterson, and coauthors Ruben Sanchez-Romero and Ravi Mill! Preprint here: https://doi.org/10.1101/2023.09.16.558065