Geometric effects of volume-to-surface mapping of fMRI data

In this work, we identify a problem with the process of volume-to-surface mapping of functional Magnetic Resonance Imaging (fMRI) data that emerges in local connectivity analysis. We show that neighborhood correlations on the surface of the brain vary spatially with the gyral structure, even when the underlying volumetric data are uncorrelated noise. This could potentially have impacted studies focusing upon local neighborhood connectivity. We explore the effects of this anomaly across varying data resolutions and surface mesh densities, and propose several measures to mitigate these unwanted effects.

Automated summary

In this study, we identify a problem with the volume-to-surface mapping process in functional Magnetic Resonance Imaging (fMRI) data, which affects local connectivity analysis. We demonstrate that neighborhood correlations on the brain surface vary spatially with the gyral structure, even when the underlying volumetric data is uncorrelated noise. This could potentially impact studies focusing on local neighborhood connectivity, but we propose several measures to mitigate these unwanted effects.