Phase Regression and Dynamic B-Field Correction Reduce Global Time Series Correlations and Increase Functional Correlations

Andrew S. Nencka¹, Andrew D. Hahn¹, Daniel B. Rowe¹

Functional connectivity magnetic resonance imaging suffers from a small signal of interest that is confounded by several signals which are not of interest. Much work has been performed to utilize nuisance regressors to reduce such noise. Here we consider the signal caused by magnetic field fluctuations, as a result of out of field of view motion, scanner instability, or bulk sample magnetization changes. We consider the phase regressor method and the dynamic B-field correction method in preliminary resting state data. Both methods reduce global voxel time series correlations and increase voxel time series correlations in expected regions of connectivity.