Switching activity in an ensemble of excitable neurons
The paper proposes two dynamical systems based on the generalized Lotka-Volterra model of three excitable elements interacting through excitatory couplings. It is shown that for some values of the coupling parameters in the phase space of systems, there are heteroclinic cycles containing three or six saddle equilibrium states and heteroclinic curves connecting them. Under certain external stimuli that transfer the system from a stable zero equilibrium state to a small neighborhood of the heteroclinic cycle, the phase trajectory will alternately visit the neighborhood of saddle equilibrium states (possibly more than once), after which it will return to its initial state. The described behavior is proposed to be used to simulate switching activity in neural ensembles. Different transients are determined by different external stimuli. The passage of the phase point of the system near the saddle equilibrium states included in the heteroclinic circuit is proposed to be interpreted as activation of the corresponding element.