Spatial and temporal resolution of dense array electroencephalography

The electroencephalogram is often assumed to have good temporal resolution but poor spatial resolution, caused by the ill-posed relationship between measured head surface potentials and the possible generators in the cortex. We describe several approaches to constraining the dense array EEG (dEEG) inverse problem by specifying the sensor positions, head geometry and conductivity, and the orientation of possible cortical sources. Furthermore, source analysis is necessary for meaningful temporal resolution of brain activity, to disambiguate the multiple cortical sources that are superposed at each sensor. New methods are proposed for identifying cerebral networks by attributing measured potentials to sources whose covariances are specified anatomical networks assessed by diffusion tractography, and for testing the validity of candidate networks through dense array neurostimulation.