Synergism and antagonism of neurons caused by an electrical synapse.

To investigate the role of electrical junction, a model system consisting of two electrically coupled neurons was studied. It was revealed that the model system generates both the in-phase pattern and the anti-phase pattern stably. Physiological condierations revealed the following. The in-phase discharge pattern (synergism) is a unique output of a electrically coupled pacemaker neurons. However, both the in-phase (synergism) and the anti-phase (antagonism) discharge patterns are possible for electrically coupled bursting neurons. We may expect other discharge patterns, such as a random discharge pattern (chaos), than the inphase and the anti-phase pattern in electrically coupled neurons. Random firing patterns in the inferior olive may be attributed to electrical synapses. Until now, we have assumed that excitation periods of two neurons were almost the same. When two periods are greatly different, various phenomena are expected. Determination of the stability of the anti-phase solution by the analytical methods, when diffusion constants are very small, is one of our future problems.