Synchronization Transition in a Pair of Coupled Non-identical Oscillators

We study synchronization phenomena in a pair of integrateand-fire (IF) oscillators with the width of an action potential. They have slightly different periodic firings each other. Such non-identical IF oscillators typically interact with each other via excitatory or inhibitory synaptic stimuli. A return map analysis gives us a systematic analysis of stabilities of the 1 : 1 phase locking states in the pair, in terms of a synaptic decaying parameter. We demonstrate transitions of the phase lockings with a small difference in their firing frequencies and different width of an action potential. Spike timing histograms are also observed in the pair with dynamical noise. The slight shifts of a synchronous state effectively induces distribution shifts in the spike timing histogram. This agrees with results observed in physiological experiments.