Bistable nerve conduction

The essence of the nerve system is to transmit information from and to different parts of the body in response to environmental changes. Here we show that a bistable conduction behavior can occur in the nerve system, which exhibits stimulus-dependent fast and slow conduction waves. The bistable behavior is caused by a positive feedback loop of the wavefront upstroke speed, mediated by the sodium channel inactivation properties, which is further potentiated by the calcium current. This provides a mechanism for the slow and fast conduction in the same nerve system observed experimentally. We show that the bistable conduction behavior is robust with respect to the experimentally determined activation thresholds of the known sodium and calcium channel families. The theoretical insights provide a generic mechanism for stimulus-dependent fast and slow conduction in the nerve system, which is applicable to conduction in other electrically excitable tissue, such as cardiac muscles.