Before revision:   For this model system, we find that random stimulation produces stable oscillations relatively often. In our model system, self-sustained patterns of excitation are generated with some frequency by random stimulation, leading us to suggest that such patterns could appear spontaneously in living tissue , either cardiac or neural, with negative consequences .
After revision:  For this model , even random spots of stimulation result in periodic rotating patterns relatively often, leading us to suggest that such patterns could appear spontaneously in living tissue , either cardiac or neural, with negative consequences .