UC Irvine

The trion represents a localized group of neurons with three levels of firing activity. Networks of a small number of trions (with structured interactions and firing dependent on activity at two previous discrete time steps) support a repertoire of hundreds of quasistable, periodic firing patterns (which can be learned). We report striking phenomena with variation in temperature T: There exist a series of phase transitions at precise values T(n), giving new repertoires of periodic firing patterns, and the average time for any initial firing configuration to project onto a firing pattern shows a quite sharp change at each T(n). Near a phase transition, in a Monte Carlo simulation, the temporal evolution wanders back and forth between sets of these firing patterns in contrast to the more structured sequential evolutions far from a T(n). © 1991 The American Physical Society.