IMPROVED DETECTION AND SPECTRAL ANALYSIS OF NEURAL TRAVELING WAVES

Travelling waves (TWs) are a prominent feature of distributed neural activity, and distinguish various cognitive states. Here, we define a extensive family of TWINS (Traveling Wave Indices) for a full and improved spatio-temporal spectral characterization of neural travelling waves. These TWINS allow for a full 3-D spatio-temporal spectral characterization that 1) are suited for irregular sampled and non-rectangular grids; 2) are well behaved for both low and high spatial frequencies; 3) provide interpretable measures of wave strength; 4) can distinguish genuine planar waves from standing waves. We prove analytical relations to classic parametric wave fits or distance-phase correlations, but improve these in several ways, while adding a full spatio-temporal spectral characterization. We apply these methods to discover spatio-temporal travelling waves in human EEG and marmoset ECoG data, revealing directional alpha travelling waves at physioliogically plausible wave speeds.