Synchronization in neurons driven by synaptic currents with multiple frequencies

In our previous study, we considered synchronization in a system of two unidirectionally coupled neurons with a chemical synapse. We analyzed the inhibitory and excitatory couplings, assuming that the firing frequency of a pre-synaptic neuron is varied. We found that the neurons easily acquire synchronization at a firing frequency higher or lower than the fundamental frequency of a post-synaptic neuron for excitatory or inhibitory coupling, respectively. In this study, we add one neuron to the previous model; the added neuron drives the previous two neurons (sub-system) by synaptic inputs. To avoid model dependence, we used the Morris-Lecar and Erisir's fast-spiking neuron models as single neuron dynamics. We found that the neurons achieved synchronization at a firing frequency lower (higher) than the synchronous firing frequency of the sub-system for the inhibitory (excitatory) synaptic connection.