Stable vortex rings of excitation in neuroelectric media

The membranes of living cells, for example, in heart muscle, support electric dipoles which invert momentarily following an electrical stimulus that exceeds a threshold. The pulse propagates as an 'action potential' at about 0.5 mm/ms in the three-dimensional 'foam' of cellular membranes. Four computer generated panels are shown which graphically represent such waves, using a continuum model with the FitzHugh-Nagumo cable equation used to model the excitable medium.<
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