Rhythmogenic effects of weak electrotonic coupling in neuronal models.

Strong gap-junctional coupling can synchronize the electrical oscillations of cells, but we show, in a theoretical model, that weak coupling can phase lock two cells 180 degrees out-of-phase. Antiphase oscillations can exist in parameter regimens where in-phase oscillations break down. Some consequences are (i) coupling two excitable cells leads to pacemaking, (ii) coupling two pacemaker cells leads to bursting, and (iii) coupling two bursters increases burst period. The latter shows that details of the fast spikes can affect macroscopic properties of the slow bursts. These effects hold in other models for bursting and may play a role in the collective behavior of cellular ensembles.