Effects of the frequency dependence of phase response curves on network synchronization

Neuronal phase response curves (PRCs) generally fall into one of two classes. Type I PRCs exhibit exclusively phase advances and lead to decreased propensity for synchronization of excitatory networks, while Type II PRCs show regions of both phase delay and phase advance and better facilitate synchronization of excitatory networks. One little-investigated feature of neuronal PRCs is that they are attenuated as neuronal firing frequency increases. Interestingly, Type II PRCs often experience greater attenuation of their phase delay region compared to their phase advance region, while Type I PRCs typically show uniform attenuation of phase shifts. We simulate large-scale excitatory networks of Morris-Lecar neurons in order to investigate the effects of these phenomena upon network synchrony, and we show that they lead to Type I network synchrony increasing with increased frequency and Type II network synchrony decreasing with increased frequency.