Towards localization of radial traveling waves in the evoked and spontaneous MEG: A solution based on the intra-cortical propagation hypothesis

In animal experiments, radial traveling waves have been recorded on the surface of the cortex. In humans, the recording by microelectrode matrices reveals only fragments of such waves. Our basic assumption is that the source of the EEG/MEG in the alpha and beta bands are radial traveling waves. Similar waves are generated in the networks of recurrently coupled neurons, where excitation is propagated through intracortical connections. We simulated traveling waves on the surface of the human brain and compared the simulation data with the experimental signals of the evoked and spontaneous MEG. Model waves were assigned a number of epicenters in the ROI on the cortical surface, different propagation velocities, and phase. The frequency of the model wave was determined from the spectral and wavelet analyzes. Correlation data allowed us to localize radial waves and to select their parameters in the postcentral sulcus with stimulation of the median nerve and in the cuneus sulcus at rest in healthy human adults. Our approach resulted in a successful reconstruction of the radial waves’ dynamics on individual brain surfaces.