Visualizing spatial resolution of linear estimation techniques of electromagnetic brain activity localization

Abstract

Various linear methods have been proposed to localize brain activity from external electromagnetic measurements. When interpreting the estimated spatiotemporal localizations, one must consider the spatial resolution of the particular approach. Locations with high spatial resolution increase the confidence of the estimates, whereas locations with poor resolution provide less useful localization estimates. We describe a "crosstalk" metric which provides a quanitative measurement of distortion at a given location from other locations within the brain. Crosstalk maps over the entire cortical surface provide a useful visualization of the spatial resolution of the inverse method.